While it would be understandable if only the galaxy crusher form was disabled since that obviously hits way too hard it's not like her lower forms are so outrageous and absolutely need to be prevented on damage to bosses as well. Ultimate Dark Fairy Queen is immensely stronger than anything below AERA's galaxy crusher level (and much easier to access to boot). I honestly don't see the need to prevent AERA's damage to bosses as long as she stays under upgrade lvl 32. Best to apply the boss immunity just to galaxy crusher phase and specifically mention the immunity there on the shorter card description of the galaxy crusher to prevent major misunderstandings.