Battle Assistance isn't working

[cryspee]

I'm trying to get the Battle Assistance Booster working - I see the battle assist icon when my party is outside of battles, but once they enter one the icon at the bottom right disappears and I can't toggle it on. I've been pressing pause then F2 to toggle it and no icon appears, and my hp/mp/trance gauge aren't affected. Am I doing something wrong? A glitch perhaps?

[cryspee]

I think I might have figured it out. It looks like I can't use battle assistance when fighting Beatrix - it works on common enemies though