This is expected from an AD/Internal Hybrid User Source.
https://docs.inductiveautomation.com/display/DOC79/AD+Internal+Hybrid
The AD/Internal Hybrid User Source is partially manageable in Ignition. Users cannot be added or removed, and their usernames and passwords cannot be changed. This is because this information resides in Active Directory, not within Ignition. Other information, such as user roles, contact info, schedules, are manageable in Ignition.