Breachstone "deleted" - Twisted Domain is empty

I just created a Breachstone, placed it in the Realmgate, and started the encounter by touching the hand. The timer started, no monsters appeared and I ran all the way to the end with no way to progress.

The timer ended, I was teleported back to the hand, monsters appeared for ~2 seconds and then went away again. There is nowhere to travel and I have to just leave.