Just a minute ago I was doing a cabal mission (retrieving daemon-guarded relics from chests) when suddenly my game froze. Enemies did not move, the 5-minute timer for the mission was frozen at 4:46, I could do nothing. But the 30-second timer on the chest was running down to Zero, without the daemon appearing. I had to ALT-F4 out of the game.
Considering that I already had 7 chests and this was the eigth, this is quite annoying, because my cabal has to do 81 of these missions :-(