The bug of berserk monsters attacking themselves was supposed to be fixed in issue 109. I haven't seen it in a while, but I just got it in pre13 from a master lich in the CoC graveyard. The message was the "normal" one for the bug -- "The master lich attacks the master lich. The master lich is killed! The master lich suddenly looks more powerful." I have a savefile immediately after the bug (none before, unfortunately) available if needed.