The "over the top" problem happens any time a resistance goes past 255; it doesn't have anything to do with a particular item. You could be wearing a couple of resistance items, then between, say, Magic Screen and SoulShield (or Element Shield), your resistances add up to much more than usual. Sloppy programming causes this to wrap around and subtract instead of add in. You can end up with low or even negative resistance.
It's a good idea to check this now and then, especially as you get deeper into the game and you find or buy more items that improve resistance. Just open the magic screen and look at each person's numbers.
Nightowl2
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