UM User Roles selection doesn’t work

For the website of our sports association we use the Ultimate Member User subscription as our membership status database. With their role, members can select the type of membership they have within our association. Since a month or 2 members can’t update their roles via the Default Profile Form. We use the Default (Dropdown), but the Roles (Radio) also doesn’t work.

The admin can change the status in the backend, and then it will be updated on the frontend for the member as well. This made us think that the fault is in the communication between the Form and the actual User Information, but we can’t seem to find where the problem lies. Everything is up to date, but we’re running our website on Php 7.4 as we can’t update to 8.1 (also trying to figure that out but thats another problem :)).

Any ideas?