Skin problem: In some head skins the top of Wolfgang's pants disappears when he gets mighty in a shirt or sweater skin

I was on a server with some friends, using the Snowfallen Wolfgang skin instead of my usual Survivor Wolfgang and the Ugly Deer Sweater + Swing Pants because it was winter in-game and I wanted to dress for the occasion, and when I went into mighty form we noticed that I was... missing something.

I didn't get in-game screenshots because I was too flabbergasted, but the bug also happened in the wardrobe menu so that shouldn't be a problem. In further testing I discovered that this happens with most shirt/body skins that don't hide leg skins and aren't specifically intended for Wolfgang, from the Lumberjack Shirt to the Mossrose Drapery.

This doesn't appear to be contained to the Snowfallen skin either: it also happens on Gladiator Wolfgang, Magmatic Wolfgang, Giant (YOTPK) Wolfgang, and Wolfman (Hallowed Nights) Wolfgang, but not Victorian or Verdant Wolfgang or any of the skins that predate the Forge.