Atlas generates rooms that cannot be accessed

So the other day I've noticed one map (it was perhaps savanna but not sure about it) that created room that was completely cut off with walls out of rest of map. It was not a big deal - I've seen some mobs there but that's it no big deal. Now I got into a map that had same inaccessible room. But now last rare mob and expedition spawned there making it impossible to finish map.

Screen below

This happened to me in the Campaign too. Leaving the Tomb of the Consort, a new instance was created that was totally disconnected from the rest of the cemetery. There was one corner that *almost* connected.