On Thelanis.
Both of my accounts are affected as well as 3 other friends that do not use the forums For me it has occurred over several logins, for the three other friends it has occurred on a combined 5 logins.
I have noticed that if I login and essentially don't do anything for 20-30 mins that the client will connect to all chat channels and will work until I switch chars or need to relog. I think that changing zones and changing party state will prevent this from happening. This usually occurs when I login and am waiting for friends or while I am finishing dinner or something.
When it connects all features are working: guild chat, party chat, friends list, etc.