When features are appended to a Hosted Feature Service that has a GlobalID field, they're assigned new, unique GlobalID values that replace the existing GlobalID values. Related tables based on a GlobalID/GUID relationship have the appended features' old rather than new GlobalID values in their GUID field. This means the change in GlobalID value renders the parent features disconnected from their related tables. For Enterprise Geodatabases, an environment setting can preserve GlobalIDs: https://pro.arcgis.com/en/pro-app/tool-reference/environment-settings/preserve-globalids.htm This video shows how to preserve GlobalID/GUID relationships between Hosted Layers/File Geodatabase feature classes and their related tables, in turn keeping parent features connected to the related records. It is best practice to make backup copies of your data before manipulating fields. Workflow Steps: 1. Add a new GUID field to the Survey A feature class, then copy the GlobalID values to the new GUID field to preserve them. 2. Add a new GUID field to the Survey B feature class to store the copied Global ID value when appending the Survey A feature class (step 3). 3. Append the Survey A feature class into the Survey B feature class. This generates new GlobalIDs for the appended features that uniquely identify them in the Survey B feature class. 4. For Survey A's related table(s), add a new GUID field to store the newly generated GlobalIDs for the appended features in the Survey B feature class. 5. Join the Survey B feature class into Survey A's related table(s) based on the related table's ParentGlobalID / Survey A Preserved GlobalID. 6. Copy the newly generated GlobalIDs into the empty GUID field. 7. Remove the join, then update the ParentGlobalID field in Survey A's related table(s) with the new GlobalIDs. 8. Append the Survey A - related table(s) into Survey B - related table(s). *BUG-000124062 is fixed at ArcGIS Pro 2.5 and will enable using Hosted Layers in this workflow. --------------------------------------------------------------------------------------------------- Follow us on Social Media! Twitter: https://twitter.com/Esri Facebook: https://facebook.com/EsriGIS LinkedIn: https://www.linkedin.com/company/esri Instagram: https://www.instagram.com/esrigram The Science of Where: http://www.esri.com