GetSigningIdentity doesn't get the user details

### Description

We are trying to ReEnroll users programmatically. In one of our environments, it doesn't work and returns "user not found" error. When we digged into it, we found that GetSiginingIdentity() is not returning the user. However, we tried to invoke GetIdentity() and it is able to get the user. The same ReEnroll() works in other environments thou. Can you please help us in resolving this - Thnx

### Steps to reproduce

_No response_