https://support.esri.com/en/Technical-Article/000013241
Problem: Esri_Anonymous is displayed in the attribute field when Editor tracking is enabled
Description
When adding a feature service, published by ArcGIS for Server, to an ArcGIS Online web map for data collectors via the Collector for ArcGIS application in offline mode, 'Esri_Anonymous' is displayed in the attribute field for the last edited user.
Cause
Editor tracking in ArcGIS for Server is not designed to transfer ArcGIS Online user account details and can only retrieve ArcGIS for Server user details. This is a known limitation that the system was not designed to accommodate.
Please design the system to accommodate this. We are limited to 10 Portal user names because we are using SQL Express. That's not enough for us now. We have added AGOL user names but they get recorded in our sql feature class as Esri_Anonymous. We want to maintain a live link to our SQL sde data and not publish a hosted feature class where we don't have a live link to the data anymore.