Bansee's power ability is supposed to raise ATK and DEF of allies and lower ATK and DEF of enemies.
Either a buff is wrong, or the incorrect ability is being granted.
Her power ability raises ATK and DEF of Allies, as expected. However... it raises ATK and lowers DEF of enemies. Enemies get the blue "ATK+" buff and the red "Def-" buff. So either she's raising ATK of the wrong characters, or the blue buff should be the red buff.
I can't really tell if ATK is actually boosted or lowered for enemies based on attacks.....