No, he's actually right. Last week on the night before the instance reset, a couple of my guild members and I got a few PuG people and headed into 10-man. It was actually a really good group, getting him into phase 3 with 6 minutes to spare on the enrage timer. But as soon as phase 3 started and the platform broke and we landed on our drakes, they despawned, and the entire raid fell to their deaths, before Malygos was even engaged again. This happened three times in a row before we called it.

Now, cut to yesterday, after the instance reset, patches full of fixes, several server restarts, etc. I did a guild run while waiting on one of healers to log on so we could hit up Ulduar, got him into phase 3 with plenty of time to spare, and the drakes seemed to be working. We got Malygos down to about 10% when all the drakes yet again despawned. However, this time they picked us up again, but when we were back up, we were all in melee range of him, and he proceeded to kill us off pretty quickly before we could figure out what happened.

So no, he wasn't just dying. This is an actual bug, which as of yesterday (4-24-09) had not been fixed.