Burial Chamber T5 Map bug

I am inside Burial Chamber (T5 Map) right now. The boss is the only monster remaining, it already summoned all of the adds and I killed them. I still can not hit the boss with attacks, still has the light over it's head.

I will wait for a while here and watch some TV if someone from GGG wants to contact me in game.

Thanks.

I just noticed, I did get the completion credit on the Atlas for this map.

You killed the boss. That boss doesn't use immortal call.