Is the ED/Max Dmg bug still a thing in helms/armor/shields?

yup

IIRC, innate ED will not be bugged, so putting maxers in an lld paly shield (ED/AR) will work perfectly (both ED and max apply). Similarly, a maxer should not bug Biggin’s Bonnet. On the other hand, adding Ed/max jewels (both on one jewel) to armor/helm/shield or adding a combination of these jewels will make the ED only apply to the part of damage not modified by integer (if you put Ed/max jewels or ED jewels in combination with max jewels, the ED will only apply to the minimum dmg and the +max will apply to the max dmg; if ed/min, then ed only applies to the max and the min will increase by integer modifier).

Just my .02

also ed/max bug doesn't apply to ranged attacks but the dmg it adds is hidden