I'm not sure if this one has been repeated, but if I'm playing a sorcerer and physically attack an enemy that can teleport, if it's at a low enough health it'll retaliate, teleport away and then die. Should it die before it teleports?
The first time it happened I didn't have any other viable monsters to kill, so I chased it across the map only to find a blood stain on the ground. In retrospect I should have noticed my exp going up, but I didn't.