I never encountered that bug and I've been playing this game straight for two days now. I found a spell or two that could use a little tweaking especially for the necros. That 'Bone Crushing' spell is a little too great. As long as I don't get killed too fast I can take out anything with that spell relatively quickly. Mix in with a few 'raise monster' spells and I right now I have three buffed up baddies protecting me while I explode the rest of the gang to bits and pieces. One other thing is pretty cool. If I go all crazy just blasting away underground every now and then I'll start to get cave ins not cause by earthquakes or support beams. It doesn't happen every time, but it does happen which I thought was a nice touch. That and as long as my undead are humoniod then they will use the healthstones all by themselves. The animals won't.
I even pumped up the difficulty level way over the recommended and still survived (barely). The only problem was staying away from their attacks. One or two hits and I'm toast, but one or two hits from me and their whole gang is toast.