Yeah, this has happened to me five times in a row with the crushing walls refusing to do their job. It doesn't trigger death, but instead deactivates the solids. Plus, there isn't a pit death trigger in the room, so I've had to restart the entire stage to get a single attempt at fighting it again.
Version 1.00.4 still has that bug. Got stuck a few times myself, getting crushed didn't trigger a death, but rather made X slip downward slowly like he's sinking into quicksand and once at the bottom of the screen, there's nothing to do other than restart the stage. The same bug also happened in the death pit just before the final boss door of Sigma 1. Missed my footing on the exploder platforms and fell down and instead of dying in the pit, I just got stuck there as well.