Same here and also the same thing happened to me last year on the Fold 2. I actually sold it because premium care was so awful. Hopefully they don't repeat this time.
Update. I just spent over a half hour on the phone and eventually they told me the system isn't updating and they're hoping to have it fixed by end of today if not tomorrow. They repeated "hopefully" several times.
I click on a tile on the members app and then enroll. It takes me to this site to register. It now recognizes my IMEI. It didn't before. https://rg2.samsungcareplus.com/us#!/auth?cid=samsungmembers_benefit_00000000&token=TJEboW-lts4YbnaN...