Well, we just were making candy runs when suddenly when going down the elevator, this happened.

I don't know what went wrong, but we were even in the middle of the stoneblocks. Of course, enemies didn't spawn until we went outside the area, to the border. We later found out the start elevator and the level went as normal though.

And of course, I made a bug report already. It is f2 though, not f12. XD