Quote Originally Posted by RiversideGuy View Post
I only have 2 copies of the chest 620 DoL gear... one is equipped on one retainer and I can NOT equip the other one to another retainer. BUT somehow I managed to do that with the 590 gear, I have 2 of that, each one of the 5 equipped to a different retainer. Trying to equip that second 620 one from my Armoury chest or my inventory, same results, will not equip.

Oh, I have NONE of that gear on my in-game MIN/BTN. They have all crafted gear.
I have no issues with that. Maybe it's because you have a duplicate of the set piece you are trying to replace in your inventory. To be able to equip the 620, you have to be able to unequip and place the other piece in your inventory.