I just logged in to my usual chat room and for some reason my avatar and username got changed to that of my other accounts. I only have a special avatar and username on one SE site and that is which I chose as my "main account" in my chat profile. I know how it's supposed to work and I know if I change it to something else, it would sync my chat appearance to that in a short while, but I didn't touch anything, it just happened on its own, and my main profile is still the same, but it displays the wrong name. The name on the main chat profile link doesn't match the name and avatar you see when you click it.
update: I just noticed that my reputation number in chat shows only the main profile's rep, and not the total network rep. Everybody else's rep seems to indicate their total sum of all reps on all sites. What's going on?
After setting it manually to my desired main site again, it seems to have been fixed. But just for posterity I'm gonna leave this in case someone else gets this and thinks they're the only one (you're not :p).
Update: I think I know what might have caused this. I asked a question on another site and the comments under one of the answers got very long and another user invited me into the chat room via the "continue this discussion in chat" which appears when the comment chain gets too long. I think this could have triggered creating the room with my username and avatar from that site and somehow changing my chat profile to match the site from which this started. That room still has my other username in its title, and now that I've fixed my profile to look as I want it to, my chat display name and my name from the room's title don't match.