Stacking Punch-through

[KnaveOfSwords]

So, another of the topics that the game doesn't address directly (the only mention of punch-through is the mods that give it), but going over to the wiki, there seem to be scattered references to mods that give punch-through not affecting weapons with innate punch-through.  Does anyone know how this actually works?

[TARINunit9]

It's more of a case that it's really hard to test. Weapons with innate punch through have a LOT of innate punch through (the lowest innate punch through, bows, can still hit like 8 enemies), whereas most punch through mods don't grant much extra punch through

Also I'm noting on the wiki that "In both cases, their innate Punch Through values will stack with any mods that grant Punch Through", so what you're finding is probably a bug