Hey there, dungeon keys and reward passes are applied one-time to the active account at time of cross-save, in this case your XBox account. While cross-save was active, the pass content was available on all linked systems because they count as in-game Eververse purchases. However when you deactivated cross-save, like Eververse cosmetics, the passes remained tied to the XBox character set. That is why you can play the DLC expansions on Steam with the Steam character set, but do not have the reward passes, they do not share or duplicate to any other separate character set. In cases where a player buys the passes and then immediately sets cross-save up, leaving the passes on the dormant account, there is a way to ask Bungie to move them to the active account. However if you've been earning rewards from the pass on the XBox character set, the above is not an option.