I fight the skeletons in the temple. At this point, there is only one undead warrior alive (well, as alive as undead can be )
The skelleton attacks himself, kills himself and this triggers cleaving stance which causes zero damage to my fighter.
(At least if I understand the tooltip correctly that is shown on the left side.)
During this fight, the enemies attacked themselves quite a lot.
My wizards casted bewildering spectacle, but I cannot see if it hit the enemy by looking at the combat log.
Edit: You can see that a skelletal sorcerer was also killed at that time. But he was standing far away from the warrior and has nothing to do with the strange behaviour of the warrior.
Edited by Madscientist, 23 November 2017 - 08:52 AM.