Hi, I run Dorian in a Highlander Paladin with Spirit of the Badlands Mirage. When a Mirage is in play, minions copied by Dorian when drawn will be unplayable and are stuck in your hand. I guess this is related to the bug that minions discovered off of a Mirage discover cannot be played.
Mirage is broken, stop using it
Currently you should only use the mirage when it gives minions that do not generate cards
Any transformation of the mirage that generate cards generate unplayable ones