Why does the value Anonymous appear in the Last update field after creating a candidate.

We are occasionally noticing that when creating candidates and saving them, the value "Anonymous" appears in the "Last Update" field. This is reflected in tables and analytics reports, and is observed after creating a candidate in Oracle Cloud HCM. However, we haven't been able to determine the conditions under which this occurs, as the user creates the candidate with a phone number, and then we want to audit who removed the phone number from that candidate. Upon review, the user who made the change is not identified. What is causing this?

Version: 25C