Ok thats good.
Suhosin is a browser to server thing, so it just affects the mp3 recorder and will not affect the red5 recordings. Actually Moodle downloads the red5 recordings in a server to server transaction.
So suhosin does kinda fit the description here. It would explain why it works on one server and not another. And why it fails at around the same point(50s) every time. And Red5 recordings work, and not mp3 ones.