Kulemak Boss's lasers never turn off even after you kill him

In the Kulemak Boss fight I died after killing Kulemak because the green beams draining my life never turn off. This makes him impossible to beat unless he's designed as a character test -- can you one-shot him or not.

Same here. Many times when i fight Kulemak after the boss dies there are white channeling lazers from the side pylons draining my life. I have tried everything, but always just die to that. Am I missing something or actually just bug?