So I got down to level 162, uncovered the hole to level 163 but decided to exit the mine using the warp sesajin. I warped to my farm to unload my inventory. Then I went back to the savannah (using the Rafflesia flower on the farm) and went back into the CoM. I clicked "go to last level" and it took me back to level 162, but, as the video shows, the hole had disappeared.
I went back to the CoM lobby using the rope on level 162, and clicked the "go to last level" again. This time it took me to a level 142. All of the holes leading up to level 162 were still uncovered (even if a rock had re-spawned on top of it) so I went through the holes to get back to 161 and, as the 2nd video shows, when I jumped into 161's hole to get back to 162, I got the infinite back screen while the music kept playing.
I stayed on that screen to see if my character would pass out since it was 00:40, but nothing happened. I had to force close the game.
Reproduction rate: I'm not sure, haven't tried again.
Game Platform: Steam PC
Game version: 1.1b-1233
Input mode: Controller.