Was the mage using Mage Hand?
(In case you’re not a D&D nerd, was there a blue, ghost-like hand to her left?)
Items carried by spells also count for multiclass criteria!
I just replayed Day 7 looking for her, and I think I realized what the problem is. She's the redheaded mage in red robes, with a skull staff that has a yellow crystal and a mage hand holding an orange crystal book. Now that I'm looking at the specific results screen, I see now that she has a bra of holding, and that's why she's supposed to get the lactation/boobs combo.