half sinew
This floor had no obstacles (neither mushroom nor stone), only monsters. I'm not sure if there had already existed a hole in this floor of Savannah mine. Once I eliminated the last monster, another hole appeared. It's not critical. I could still proceed to the next floor.
muted lotus
Hello! Thank you for your report, and I'm sorry for not getting back to you sooner.
Can you let us know the platform you use to play? Have you tried to restart the game and go to the same floor again to see if the issue persists?
half sinew
I played on Steam. The issue seemed to disappear once restarted. Thank you.