[InsainArcaneBirdbrain]

Many of the newer cloth-type materials added have hidden weight modifiers that aren't outlined in their text description. I'm unsure if the weight mods themselves are the bug or if the hover-over description are simply just wrong, but these are the ones I found that have the discrepancy:

Sandcloth: +1 Weight
Toadscloth: +1 Weight
Spidersilk: +3 Weight