It was on the level with a lot of boxes stacked vertically, I changed to a big size and it teleported me out of bounds on the lower left corner of the map :)
Ok I know what's happening, for now i can fix it by just making the walls thicker, but that isn't a real solution. The fact is that I coded all of the phsics myself without using any phisics engine, so getting everything right is pretty hard hahaha! btw I'm trying your game asap!