Graveyard Boss is untargetable, character stuck in the boss room

Hi,

the Graveyard Map boss that's supposed to spawn after a couple of waves is just standing there, being untargetable. I've been in that room for 10 minutes now, the boss encounter is still ongoing (i.e. I can't leave the room).
This has now happened 2/2 times, and is possibly related to the Ice Nova skill I'm using.



Someone kill my goddarn map boss please.

Not related to boss skill just happened to me playing Firestorm Ignite