I have a different problem but also - it started today night:

I didn't drop/etc but my gtalk contacts now shows OFFLINE. In the same time I am seen to them fine and we are able to exchange messages. If I go to conversation, I can see their real status (online or away).

GTALK call button disappeared. So, I guess - it is yet another attempt to prevent voice/video calls through gtalk for Maemo phones.

BTW, syslog shows that status updates now are not recognized (name is not recognized).