Hey there, when you earn items while playing on a DLC expansion, you can still use those items in situations where you do not have the DLC. One example would be using cross-save, owning Beyond Light on one platform but not another, once earned on the former, the weapons are still usable on the latter. Another example would be when Beyond Light was a part of a Game Pass offer on console, it was a part of it, and then it got removed. There are other examples - accessing it through Game Sharing, and then stopping the sharing, for example. The Stasis subclass however is not the same. It is hard locked to owning Beyond Light on the platform you are playing on. (Same for Lightfall and Strand). According to Crimson.Report, you do not own Beyond Light and so you can't equip the Stasis subclass. You must have been accessing it through a method like one of the above, but don't actually have it in your PSN purchases.