I think I know what's happening but I'm not entirely sure yet (your observations do match what I believe though). Do those problems only occur if the accounts were not fully signed in yet before you connect to the WLAN (i.e. the availability indicator is still blinking)? I think that Telepathy/TelepathyQt4 ignores the presence change during reconnection phase which may be tricky to solve as I have not found a method in the API to forcefully interrupt the reconnection attempt.