As you can see here, the corridor is in fact not endless :( it just hits a point after walking for a bit where it goes into the void, but your shader is also producing a bug that it update it properly so it create a funky artifact.
Yeah that is an artifact even from my old game "Desolate dread" I think it does that because the renderer needs updates to write or because it doesn't use a skybox yet
Ahhh yeah, that would do it, but unfortunately your game is false advertisement because it was in fact, not endless :P. (not sure why it happens though, just walking for a minute makes it happen)
