I played on Xbox since launch, recently got a PC and enabled cross-save, aware that my DLC would not transfer (i think that's silly but that's not the point of the post)
I purcahsed TFS on Steam since that will be where I am playing, and I encountered the issue in the photo.
You cannot swap off of prismatic if you unlocked, but no longer have access to, the strand subclass because it defaults to trying to select it (i was on arc before)