Yeah, we are aware of it. We don't know what causes it though. The code is very short, so it should've been easy to find, but we spent 3 hours trying to fix it and then gave up. We thought it wouldn't be that bad since it only happens when you undo near metal crates. That's what the warning in the description is about.
Anyway, thank you so much!
PS: There's a video in the description in case you wanna check the solutions for those later levels!