That's certainly what it sounds like -- or contaminated powder that simply doesn't burn, or doesn't burn properly.
Absolutely, get some from the same set and tear them down and see what you can find in there.
Attention Brass rats and other reloaders: I really need .327 Federal Magnum brass, no lot size too small. Tell me what caliber you need and I'll see what I have to swap. PM me and we'll discuss.