It may not be anything to do with your daughter’s credentials. Your daughter seems like she’d be an excellent fit for Oberlin.
I don’t know if Oberlin is need-aware or not, but it’s possible that she may have been deferred based on financial reasons and they want to wait to see how much they can offer in financial assistance to all their accepted students. Oberlin is experiencing a financial challenge right now as described in this Inside Higher Ed article:
Best of luck to you and your daughter!