It is, but only for melee attacks like jab, whirlwind, etc
Missiles get full effect; u can go put it on maxroll and see your true damage
Yeah, seems like your right, I guess it does affect only the character screen will reflect the bug but it's not actually the case.
This is what I was able to find online :
ED and max or min jewels work in weapons without any problems, but for ALL non-weapon jewels:
Having an ED+max jewel in a item: the ED% will only effect min damage
Having an ED+min jewel in a item: the ED% will only effect max damage
Having an ED+min+max jewel in a item: the ED% will have no effect
If an item already has base ED on it, such as the ED that spawn on circlets or ED/AR paladin sheilds, max or min damage jewels will work as normal
Having an ED+max jewel in an item with base ED: the total ED will only effect min damage; the max damage will work as normal
So because the ED on the jewel is affected at the time of socketing, the order in which multiple jewels are inserted actually matters.
Simple example with 3 jewels with just 1 mod on each (ED,min,max), inserted on a 3-sockets normal non-weapon item:
ED,min,max or ED,max,min -> no bug
min,ED,max -> ED not affecting minimum melee attack damage
max,ED,min -> ED not affecting maximum melee attack damage
min,max,ED or max,min,ED -> ED completely ignored for both melee and ranged attack damage
Note for ED+min OR ED+max,
the final attack damage displayed on the character screen will reflect the bug for ranged attacks, despite it's not actually the case.