Maybe not necessarily a bug, more of an oversight I think-
The Submerged Machine, being an underwater area, requires that people very frequently dive and then resurface for air. Occasionally on a dive monsters might spawn, causing some awful trouble and making things adequately difficult to explore down there.
The trouble arises in that constant resurfacing for air, by the time you go down again, then come back and go down again, (all of 4 minutes, in my case) The spawns are back and you have to fight them once again.
I think the spawn time could be extended so that there's more time to explore between enemies, especially considering the enemies seem to have the awful tendency to just appear 10 feet away as you go through a particular tunnel and bomb you with spells. It's rather annoying that they don't even appear to really come from anywhere. My thought is more that they're just supposed to be there once per group, really, like the spawns in the bowels are, but the person who built the area didn't take into account oxygen and that people have to come up for air.