Where in the description does it say expose cannot be inflicted if a target already had expose before an attack? Regardless of zeta Finn, it seems unfair to change how a mechanic of the game works for only 3 toons, not even a whole faction, just some of the toons in a single faction.
As in the video above Darth Sidious reapplied expose after attacking a target with expose. So the original concept/mechanic still works, and Jyn allows multiple expose to stack as long as the target isn't damagd.
To me the bug is not replying expose, and any clarification to say certain toons can't reapply it, to me, is a case for a refund. I will certainly reconsider working on the Resistance faction.