I have been playing with Babi-Onna a bit recently, and notice when she poses she doesn't always activate Mirage Robe. I'm not sure if this is intentional or not because when it happens it kills the run. This isn't immediate though, it happens when you get other weapons. The other weapons will work as they're suppose to, but Mirage Robe only works sometimes. When it does work it only shoots out about one or two mirages. I'm not sure if it is because of my presets but if others want to see if they can replicate it here is my set up:
Babi-Onna (all shop upgrades except curse are active)
Modifiers:
Hurry, Arcana, Limit Break, Inverse
Cards:
XII - Out of bounds
XIV - Jail of Crystal
Eggs: ON
Map: Dairy Plant (also Inlaid Library)
This glitch only seems to effect Babi-Onna, as other characters with the same setup get Mirage Robe to work properly.