I also get the "Invalid display" messages. I use two external displays while at work (one plugged into each of the two mini displayports in my Retina Macbook Pro, and after unplugging them I find that I get "Invalid display" messages coming in pairs ("Invalid display 0x3c0c07c2" and "Invalid display 0x3c0c07c1"). I assume there is one for each of the displays.
It appears that _every_ app that was running when the external displays were connected trigger these messages. They can reliably be triggered by clicking on one such app to give it focus when it did not have focus before, or by copying/pasting from the clipboard (in which case two pairs are trigered each time).
For example, here is some output from /var/log/system.log annotated by what I did at the time:
Dec 5 20:39:49 mib104303i Terminal[581]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 20:39:49 mib104303i Terminal[581]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
# click on google chrome to give it focus
Dec 5 20:39:55 mib104303i Google Chrome[4653]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 20:39:55 mib104303i Google Chrome[4653]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
# click on terminal to give it focus
Dec 5 20:39:56 mib104303i Terminal[581]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 20:39:56 mib104303i Terminal[581]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
# click on google chrome to give it focus
Dec 5 20:39:56 mib104303i Google Chrome[4653]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 20:39:56 mib104303i Google Chrome[4653]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
# click on terminal to give it focus
Dec 5 20:39:57 mib104303i Terminal[581]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 20:39:57 mib104303i Terminal[581]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
# click on google chrome to give it focus
Dec 5 20:40:29 mib104303i Google Chrome[4653]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 20:40:29 mib104303i Google Chrome[4653]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
# click on terminal to give it focus
Dec 5 20:40:30 mib104303i Terminal[581]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 20:40:30 mib104303i Terminal[581]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
# click on google chrome to give it focus
Dec 5 20:40:31 mib104303i Google Chrome[4653]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 20:40:31 mib104303i Google Chrome[4653]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
# click on terminal to give it focus
Dec 5 20:40:31 mib104303i Terminal[581]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 20:40:31 mib104303i Terminal[581]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
# click on google chrome to give it focus
Dec 5 20:40:37 mib104303i Google Chrome[4653]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 20:40:37 mib104303i Google Chrome[4653]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
# click on terminal to give it focus
Dec 5 20:40:38 mib104303i Terminal[581]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 20:40:38 mib104303i Terminal[581]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
# click on iCal to give it focus
Dec 5 20:40:48 mib104303i Calendar[4507]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 20:40:48 mib104303i Calendar[4507]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
# quit iCal
Dec 5 20:40:50 mib104303i Calendar[4507]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 20:40:50 mib104303i Calendar[4507]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
# click on terminal to give it focus
Dec 5 20:40:50 mib104303i Terminal[581]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 20:40:50 mib104303i Terminal[581]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
# restart iCal
# click on terminal to give it focus
Dec 5 20:41:01 mib104303i Terminal[581]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 20:41:01 mib104303i Terminal[581]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
# click on google chrome to give it focus
Dec 5 20:41:02 mib104303i Google Chrome[4653]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 20:41:02 mib104303i Google Chrome[4653]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
# click on terminal to give it focus
Dec 5 20:41:03 mib104303i Terminal[581]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 20:41:03 mib104303i Terminal[581]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
# click on iCal to give it focus
# click on terminal to give it focus
Dec 5 20:41:04 mib104303i Terminal[581]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 20:41:04 mib104303i Terminal[581]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
# click on iCal to give it focus
# click on terminal to give it focus
Dec 5 20:41:06 mib104303i Terminal[581]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 20:41:06 mib104303i Terminal[581]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
# cmd-C to copy in terminal
Dec 5 20:45:22 mib104303i Terminal[581]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 20:45:22 mib104303i Terminal[581]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
Dec 5 20:45:22 mib104303i Terminal[581]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 20:45:22 mib104303i Terminal[581]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
# cmd-C to copy in terminal
Dec 5 20:45:23 mib104303i Terminal[581]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 20:45:23 mib104303i Terminal[581]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
Dec 5 20:45:23 mib104303i Terminal[581]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 20:45:23 mib104303i Terminal[581]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
# cmd-C to copy in terminal
Dec 5 20:45:24 mib104303i Terminal[581]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 20:45:24 mib104303i Terminal[581]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
Dec 5 20:45:24 mib104303i Terminal[581]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 20:45:24 mib104303i Terminal[581]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
# cmd-C to copy in terminal
Dec 5 20:45:24 mib104303i Terminal[581]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 20:45:24 mib104303i Terminal[581]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
Dec 5 20:45:24 mib104303i Terminal[581]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 20:45:24 mib104303i Terminal[581]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
# cmd-C to copy in terminal
Dec 5 20:45:27 mib104303i Terminal[581]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 20:45:27 mib104303i Terminal[581]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
Dec 5 20:45:27 mib104303i Terminal[581]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 20:45:27 mib104303i Terminal[581]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
# switch to google chrome to give it focus
Dec 5 20:46:03 mib104303i Google Chrome[4653]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 20:46:03 mib104303i Google Chrome[4653]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
# cmv-v to paste
Dec 5 20:46:08 mib104303i Google Chrome[4653]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 20:46:08 mib104303i Google Chrome[4653]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
Dec 5 20:46:08 mib104303i Google Chrome[4653]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 20:46:08 mib104303i Google Chrome[4653]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
# cmv-v to paste
Dec 5 20:46:10 mib104303i Google Chrome[4653]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 20:46:10 mib104303i Google Chrome[4653]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
Dec 5 20:46:11 mib104303i Google Chrome[4653]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 20:46:11 mib104303i Google Chrome[4653]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
# cmv-v to paste
Dec 5 20:46:13 mib104303i Google Chrome[4653]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 20:46:13 mib104303i Google Chrome[4653]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
Dec 5 20:46:13 mib104303i Google Chrome[4653]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 20:46:13 mib104303i Google Chrome[4653]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
# cmv-v to paste
Dec 5 20:46:15 mib104303i Google Chrome[4653]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 20:46:15 mib104303i Google Chrome[4653]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
Dec 5 20:46:15 mib104303i Google Chrome[4653]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 20:46:15 mib104303i Google Chrome[4653]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
# cmv-v to paste
Dec 5 20:46:18 mib104303i Google Chrome[4653]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 20:46:18 mib104303i Google Chrome[4653]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
Dec 5 20:46:18 mib104303i Google Chrome[4653]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 20:46:18 mib104303i Google Chrome[4653]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
# click on terminal to give it focus
Dec 5 20:46:33 mib104303i Terminal[581]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 20:46:33 mib104303i Terminal[581]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
Also, I'm not sure what triggers it, but some applications will freak out and report the "Invalid display" message a bunch of times at once. For example, earlier this afternoon I see entries from Dock in which it printed 8 pairs of "Invalid display" messages in the same second (there are a few instances of this pattern later in the afternoon):
Dec 5 13:44:48 mib104303i Dock[592]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 13:44:48 mib104303i Dock[592]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
Dec 5 13:44:48 mib104303i Dock[592]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 13:44:48 mib104303i Dock[592]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
Dec 5 13:44:48 mib104303i Dock[592]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 13:44:48 mib104303i Dock[592]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
Dec 5 13:44:48 mib104303i Dock[592]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 13:44:48 mib104303i Dock[592]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
Dec 5 13:44:48 mib104303i Dock[592]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 13:44:48 mib104303i Dock[592]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
Dec 5 13:44:48 mib104303i Dock[592]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 13:44:48 mib104303i Dock[592]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
Dec 5 13:44:48 mib104303i Dock[592]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 13:44:48 mib104303i Dock[592]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
Dec 5 13:44:48 mib104303i Dock[592]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 13:44:48 mib104303i Dock[592]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
Also, some apps seem to be completely freaking out about this situation.
For example, f.lux (which is updated to version 23.0) was spewing approximately 500 invalid display messages _per_minute_ once the displays were disconnected (until it was quit and restarted, after which it is fine).
These are actually a bit more interesting, as in addition to the "CGSCopyDisplayUUID" variant, there is also even more instances of "CGSGetSizeOfDisplayTransfer".
For example:
Dec 5 20:08:49 mib104303i Flux[1086]: CGSGetSizeOfDisplayTransfer: Invalid display 0x3c0c07c1
Dec 5 20:08:49 mib104303i Flux[1086]: CGSGetSizeOfDisplayTransfer: Invalid display 0x3c0c07c2
Dec 5 20:08:50 mib104303i Flux[1086]: CGSGetSizeOfDisplayTransfer: Invalid display 0x3c0c07c1
Dec 5 20:08:50 mib104303i Flux[1086]: CGSGetSizeOfDisplayTransfer: Invalid display 0x3c0c07c2
Dec 5 20:08:50 mib104303i Flux[1086]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
Dec 5 20:08:50 mib104303i Flux[1086]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 20:08:50 mib104303i Flux[1086]: CGSGetSizeOfDisplayTransfer: Invalid display 0x3c0c07c1
Dec 5 20:08:50 mib104303i Flux[1086]: CGSGetSizeOfDisplayTransfer: Invalid display 0x3c0c07c2
Dec 5 20:08:50 mib104303i Flux[1086]: CGSGetSizeOfDisplayTransfer: Invalid display 0x3c0c07c1
Dec 5 20:08:50 mib104303i Flux[1086]: CGSGetSizeOfDisplayTransfer: Invalid display 0x3c0c07c2
Dec 5 20:08:50 mib104303i Flux[1086]: CGSGetSizeOfDisplayTransfer: Invalid display 0x3c0c07c1
Dec 5 20:08:50 mib104303i Flux[1086]: CGSGetSizeOfDisplayTransfer: Invalid display 0x3c0c07c2
Dec 5 20:08:50 mib104303i Flux[1086]: CGSGetSizeOfDisplayTransfer: Invalid display 0x3c0c07c1
Dec 5 20:08:50 mib104303i Flux[1086]: CGSGetSizeOfDisplayTransfer: Invalid display 0x3c0c07c2
Dec 5 20:08:50 mib104303i Flux[1086]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
Dec 5 20:08:50 mib104303i Flux[1086]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 20:08:50 mib104303i Flux[1086]: CGSGetSizeOfDisplayTransfer: Invalid display 0x3c0c07c1
Dec 5 20:08:50 mib104303i Flux[1086]: CGSGetSizeOfDisplayTransfer: Invalid display 0x3c0c07c2
Dec 5 20:08:50 mib104303i Flux[1086]: CGSGetSizeOfDisplayTransfer: Invalid display 0x3c0c07c1
Dec 5 20:08:50 mib104303i Flux[1086]: CGSGetSizeOfDisplayTransfer: Invalid display 0x3c0c07c2
Dec 5 20:08:51 mib104303i Flux[1086]: CGSGetSizeOfDisplayTransfer: Invalid display 0x3c0c07c1
Dec 5 20:08:51 mib104303i Flux[1086]: CGSGetSizeOfDisplayTransfer: Invalid display 0x3c0c07c2
Dec 5 20:08:51 mib104303i Flux[1086]: CGSGetSizeOfDisplayTransfer: Invalid display 0x3c0c07c1
Dec 5 20:08:51 mib104303i Flux[1086]: CGSGetSizeOfDisplayTransfer: Invalid display 0x3c0c07c2
Dec 5 20:08:51 mib104303i Flux[1086]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
Dec 5 20:08:51 mib104303i Flux[1086]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 20:08:51 mib104303i Flux[1086]: CGSGetSizeOfDisplayTransfer: Invalid display 0x3c0c07c1
Dec 5 20:08:51 mib104303i Flux[1086]: CGSGetSizeOfDisplayTransfer: Invalid display 0x3c0c07c2
Dec 5 20:08:51 mib104303i Flux[1086]: CGSGetSizeOfDisplayTransfer: Invalid display 0x3c0c07c1
Dec 5 20:08:51 mib104303i Flux[1086]: CGSGetSizeOfDisplayTransfer: Invalid display 0x3c0c07c2
Dec 5 20:08:51 mib104303i Flux[1086]: CGSGetSizeOfDisplayTransfer: Invalid display 0x3c0c07c1
Dec 5 20:08:51 mib104303i Flux[1086]: CGSGetSizeOfDisplayTransfer: Invalid display 0x3c0c07c2
Dec 5 20:08:51 mib104303i Flux[1086]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
Dec 5 20:08:51 mib104303i Flux[1086]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 20:08:51 mib104303i Flux[1086]: CGSGetSizeOfDisplayTransfer: Invalid display 0x3c0c07c1
Dec 5 20:08:51 mib104303i Flux[1086]: CGSGetSizeOfDisplayTransfer: Invalid display 0x3c0c07c2
Dec 5 20:08:51 mib104303i Flux[1086]: CGSGetSizeOfDisplayTransfer: Invalid display 0x3c0c07c1
Dec 5 20:08:51 mib104303i Flux[1086]: CGSGetSizeOfDisplayTransfer: Invalid display 0x3c0c07c2
Dec 5 20:08:52 mib104303i Flux[1086]: CGSGetSizeOfDisplayTransfer: Invalid display 0x3c0c07c1
Dec 5 20:08:52 mib104303i Flux[1086]: CGSGetSizeOfDisplayTransfer: Invalid display 0x3c0c07c2
Dec 5 20:08:52 mib104303i Flux[1086]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c1
Dec 5 20:08:52 mib104303i Flux[1086]: CGSCopyDisplayUUID: Invalid display 0x3c0c07c2
Dec 5 20:08:52 mib104303i Flux[1086]: CGSGetSizeOfDisplayTransfer: Invalid display 0x3c0c07c1
Dec 5 20:08:52 mib104303i Flux[1086]: CGSGetSizeOfDisplayTransfer: Invalid display 0x3c0c07c2
Dec 5 20:08:52 mib104303i Flux[1086]: CGSGetSizeOfDisplayTransfer: Invalid display 0x3c0c07c1
Dec 5 20:08:52 mib104303i Flux[1086]: CGSGetSizeOfDisplayTransfer: Invalid display 0x3c0c07c2
Dec 5 20:08:53 mib104303i Flux[1086]: CGSGetSizeOfDisplayTransfer: Invalid display 0x3c0c07c1
Dec 5 20:08:53 mib104303i Flux[1086]: CGSGetSizeOfDisplayTransfer: Invalid display 0x3c0c07c2