Secret

Same thing happens to me, it freezes when we try to communicate. And mojang won't do anything. And Johnny is right, I found that out when I first froze, I closed it out immediatley. For some reason, in the pigraid server's lobby I can chat without worry, and in singleplayer I can chat(Which is worthless). So, I arrange to meet in the creative server on pigraid with players in the lobby, meet them in creative, build with them (And communicate with signs). It's really the only way I can enjoy socializing.

I have this exact issue, the only time I can chat without crashing is whenever I'm in the pigraid server lobby, and nobody seems to want to chat with me there. So I try to find creative servers and use signs to communicate. It seems like mojang doesn't give a crap. Lifeboat crashes chat for me too, and every other server.