I'm not fully sure why this happens but there are certain places in the game where you can slide across objects without holding forward at all, but you lose the ability to jump, as if what you're walking on isn't actually ground. This occurs most noticeably on diving board steps and the very edge of almost any platform, but through speedrunning I've actually found out that you can do it anywhere in the game by pressing jump, then jumping again just as you land on the ground. Sounds like a cool little timesave yeah? Well...turns out, if you had an area with a low enough ceiling...uhh, well, let's just say the game doesn't like it.