Frozen Cabins Map Boss - Ghostflame Ability Persists After Death

Killed the boss of the Frozen Cabins Map as he was casting the Ghostflame ability, and the damaging circle stayed on the ground. It continues to damage me.
Killed with ignite, via Ethereal Knives.
Cinderswallow might also have been active, not sure though.

Bug Report Reference Number: 3,218,265,066