Stuck in Lich side area / abyssal depths

Hi guys,

perhaps I am missing something.
I died during a lich fight in the second side area. I tried to get back in time but failed. When I was back in the main boss room, there was no time left on the timer and every side area was open. I was curious and went into the third side area but was stuck there.
There was no door back and I can't open a portal in the abyssal depths.

You can see in the screenshot the opened map, without any way back.

Did I miss something?

Something similar happened to me:
I died in the second side room but still killed the spire. After continuing the fight and killing the third spire, there was no return portal, so the only exit was logging out. The fight could still be completed.

Going back into the second room and then into the third one allowed an exit from the third room to be created.



After entering the second and then the third room again: