after acquiring the exotic weapon Legend of Acrius by completing the arms dealer strike, the weapon can neither be stored in the vault or reacquired from the collections section. Is that intended to be so?
-
Not a glitch, you haven't finished the quest yet. When you complete the strike you are given a strike version of the weapon which has a locked power level, can't be transferred to other characters or stored in the Vault, can't be infused, and only holds one shot. To get the final version of the gun you need to inspect the quest to proceed to the next step.