This is related to certain critical exception in servers. It's easily fixable but crashes either the room list or whole TB. I've notified sir about it, so for now all we can do is to fix it when it happens. Posting new threads on support will be useless tho, so if this happens just hop in on #support and poke a GM.
I fixed it for now.
[re] | #Polska qui hic minxerit aut cacaverit, habeat deos superos et inferos iratos