Following up on this post:

It happened again, and I’m not sure why. I hadn’t hooked any other monitors up to the server since I had originally set it up. The only thing I suspect is I tried changing the display settings colors to thousands instead of millions to speed ARD up some. There’s definitely a bug… I’ll be watching Apple for an update.

So I tried hunting the problem down a little harder this time, knowing it was in ~/Library/Preferences somewhere. Sadly, I’m still not exactly sure where, but I have a suspicion it’s in the ByHost folder, in one of the display .plist files. Either that or it’s one of the systempreferences .plist files in ~/Library/Preferences.