if you fire up a normal [not modded or hacked] single player Bard does it still play up?
Alright, i have an answer now.
I did try a single player bard game (+Lae'Zel / Shadowheart / Gale), and once i reach level 5... Tadaaa !
... Same bug.
You can see it being greyed out on Lae'Zel, which shouldn't happen, and you can also see it is not in the reaction system anymore.