Hmm. I have a lich on my crew (got lucky and got a REALLY powerful migrant... started with 13 in archery... he's pretty much a one man army, and his only job is to be a refuse hauler and military dwarf). I don't know if having him go in and out of the death pit all the time makes a difference in the odds of popping up golems, but it appears to. Either that, or it's the fact that I do the minecart stockpiling to conserve FPS. I've noticed a lot of the special effects in the game will hit everything standing on a single tile.
That or maybe it just has to do with the number of bones you get. I have a very healthy corpse industry going on.
Also... I keep getting bone golems that are former people for some reason. I think from trade caravan casualties, courtesy of my local warlocks (they siege me like three times a year... kind of annoying, honestly). It's never been a problem- they don't turn into ghosts or spawn unhappy thoughts or anything. But I have a bunch of named golems that are herbalists or traders or some such.
But he's never actually given me any trouble. I do have a handful of outdoor zones designated for my golems, however. So they're stored safely away from all my industries and dwarves, and right in the path of any would be invaders. Maybe you had one of those "overcrowded, so attack" like dogs tend to do?
