I am currently investigating a problem in which users appear to be disconnected when new users join. I have found and fixed a bug which might cause this, but whether this is in fact responsible is hard to tell without testing.
I should say that bugs that cause loss of synchronisation with a server can be extremely hard to find (to give some idea of how hard, it once took two people four months to find - not to fix, just to find - one such error), so if this does occur, it may be a very long time before it is rectified.
(Also, losing synchronisation with the server might also be caused by the server crashing or being restarted for testing purposes).