The bug only applies to jewels that have both +ed and +max dmg on them. It applies the ed to the minimum weapon dmg instead of the whole range when socketed off weapon. Using plain +ed jewels or plain +max dmg jewels work fine. Sorta.
Off weapon ed is added at the end of the equation without additional modifiers so it's not as effective unless you have a lot of +min/max dmg from other sources or a weapon with a huge base damage like Grief. The +300% enh dmg from Fortitude works nicely in that scenario. Off weapon dmg also improves kick dmg for sins.