A user may register multiple credentials of the same type.
For example, OldMobile and NewMobile.
Instead of the NewMobile overwriting the OldMobile credential they get registered as 2 separate credentials.
Same goes with email address.
Release : 12.8
Issue fixed on Drop 8 Jun 04 (22/June/2022)
The fix will ensure the existing credential type will be overwritten but will not remove any existing duplicate credential types.