Just to let Arumbus know.. my materials issue wasn't what I thought it was after all.  You actually had the right idea.  My materials were intersecting with the skin texture on the model.  I took a closer look at the top on my test model and there was a couple dozen small spots I couldn't see that hadn't smoothed out and were colliding.  Added a bit of smoothing with decent collision points to the top and it worked fine.