We had a similar experience to @SeekingPam:
This is similar to what happened to my D with USC. After she got accepted ED by Pomona, she emailed the schools where she had RD apps pending (within a few days of getting the ED acceptance and FA response). Some didn’t respond, but most sent an email acknowledgement (some with a nice note wishing her well at Pomona) and some showed an update on the portal, if they had one. But her attempt to withdraw from USC didn’t work and in February she was surprised to be accepted and invited to interview for one of their big scholarships. She was chagrined because she had several classmates applying to USC and hoping to get such invitations. She then called USC admissions and left messages, tried unsuccessfully to withdraw on the portal, emailed the local rep (who said he’d take care of it), and sent several more emails. She continued to get admissions mail from USC for a couple months, including increasingly urgent demands for the housing deposit. Finally they seemed to get the message she wasn’t coming.