@IsramI have a similar problem … One of my testing accounts can’t ever remember the ‘repeat password’ content. Any time I edit the account that field is red stars and needs me to update it. (I don’t use HRIS for user accounts; we self-register)
The closest I have found to getting my password to stick is to 1) make whatever changes I need in the account, 2) make certain the password is in place, 3) sign out of my admin account, and 4) log in with the username of the problem account. SOMETIMES that gets the password to stick.
In your case, are you updating BOTH the username and email address fields with the new address? Re-reading your post makes me think you are updating only the email address and expecting the username to follow suit. I’ve never seen that work. We just update both fields.
Another idea … put the changes into a .csv with the current username/email address, and use the new username field to change it.