After iMac wakes from sleep, three monitors turn on, go black for a couple of seconds, then back on again.
I have two external monitors connected to Thunderbolt 2, one a VGA monitor and the other an HDMI monitor. After waking from sleep all three monitors come on, then all three go black for a couple of seconds and then back on and then work fine until next time it goes to sleep. Same thing each time it wakes up.
An Apple support tech told me recently that this is a known problem, but I don't see any help here in the Communities.
I can live with this, but it is annoying. I'm running BigSur 11.5.2 in a mid 2015 iMac Retina 27".
Anyone else see this problem? Any fixes?
Thanks,
iMac 27″, macOS 11.5