That project is already fully registered. After registration, there is a period of time where other people can dispute it (that’s stage 2), but it does not affect the ability of the project to be S/R.
The fact that the project is not yet on the S/R says to me that it just has not been S/R’d since it was converted. Check Project > Project Properties and Settings and Project > Users, Roles and Permissions. If the project shows as registered in the Project Properties and Settings, then everything is fine with the registration.
FWIW, You can change the normalization of the project without needing to convert it.