It happened couple of times, actually. It happened for sure in mlmurdercrow, when I was checking out the random multiplayer level out of curiosity (as I've never actually had a chance to play one back in the days on my 1.00g Jazz). There is a bouncer power-up on top of 1-tile high slope. I ran to it from the left side, Jazz started pushing it but the object did not move. That's when I decided to make a jump and he just got stuck in the ground. When I repeated jump he was just diving in the ground deeper and deeper... I just tried it out again and exactly the same thing happened.