My two issues:
Sometimes, the system kicks me out, or more correctly, logs me out. (Firefox issue, forum, or both?).
The notification sytem is unreliable. I precisely mean the "bell". People post here and there and sometimes I don't get notified. (I've checked my preferences to get notifications about my posts as well as other's).
Fortunately, I'm not having those problems today. I guess these are known issues that are already being considered.