any chance the new food is higher carb?
I think i'd wait a little bit longer, only because i can't tell if maybe this is a new bounce, not the same bounce from 1/19. Counting forward 3 days would've meant she'd have cleared it by this morning, but here she is still high. i wonder if she saw anything lower while you were at work on 1/20 or 1/21.
maybe someone else will have some insight to offer.