I've got the exact same issue. Disconnected from chat (nobody can see what I'm writing and I can't see what others have written). This can happen randomly but most times I've gotten it that right after I exited a duty.
When it happens, I can do everything else and some time after it happened (5-10 minutes after), I get booted from the game. The errors I get are usually 90002, but also sometimes 90001.
As a side note, I've got the same provider as the person above me (Telenet in Belgium).