Iron citadel not completing

Hello,
This is the 3rd Iron citadel i'm doing since last patch (0.1.1) and everytime i finish the citadel, it doesnt complete. It's always with 1 monster remaining but i fully cleared the map and there isn't a monster left. There is no golden skull showing either. Lucky for me this hasn't blocked my route to another atlas node, but it did for one of my friend.

https://imgur.com/a/cuPAokj

Having the same issue #bump