I don't know what it is but they don't seem to obey me much as it is and when you run out of gold it's like billion times worse. And what's weird, I found a massive pile of gold to dog, marked it and none of the Imps wanted to dig it. Even if I tossed them there, they just ran away. And you know what happens when minions run for too long without gold. It only gets worse.

This is in mission where you're in the middle, surrounded by lava and you have to build bridge to get over, 5th or 6th mission I think.

Not to mention in this same mission framerate dropped to nearly unplayable levels for no real reason. Or does just the exploring of the map affects performance so much? On a 4,2GHz quad with increased Dosbox CPU cycles? Hm...