Slowing potency of debuffs on you

what is this supposed to apply to? there are a number of things it doesn't. one im experiencing right now is Spider Webs, says you are slowed, and sure enough im slowed even though i have over 100% reduced slowing potency of debuffs

spider web is a debuff that slows, and my reduced slowing potency of debuffs isn't applying to it. seems like a bug

Same thing for temporal bubble. It's not affected by either slow potency reduction, nor the Wanderlust boots that should make you unaffected by slows (haven't tried pathfinder's Relentless Pursuit, but I can assume it should be the same). Hopefully GGG fixes this as it makes playing melee a pain with no proper solutions for it.