Same problem, several times. I do not have the eBay app nor were any of my updates for 17+ apps (that I know of).
Easiest workaround: "Update All" on your iPhone instead.
This is a pretty annoying bug as the "Update All" feature, both on the iPhone and iTunes is a great feature. And it's pretty sad that the iPhone can take care of it no problem but a program as advanced as iTunes cannot. I hope this gets fixed ASAP.
As this seems like a true bug, I will be reporting this bug as feedback here, and I recommend you do the same...
http://www.apple.com/feedback/itunesapp.html