Kadex appears, I hit him and he does his teleport copy thing. Then I stun/stagger plague marine, execute for AP, then kill a Nurgling. But the moment it dies, Kadex recalls his copies and the Nurgling that died gains 3-5 hp but the model is dead.

Now the game is stuck with me watching a dead Nurgling's status bar wtih 3-5 hp.

I did solve this by killing the clones of Kadex first but still this was a weird thing to happen.