I have a workbench that was written in Form 2024.1 that takes data from a file geodatabase, runs a bunch of tests on it, and eventually writes to two Portal feature services. I published the workbench to Form 2024.1 and it worked without issue. When we upgraded to Flow 2025.1, the process stopped working, erroring with “ArcGIS Portal Feature Service Writer: 'addResults' error for a feature in '<feature service name>'. The error code from the server was '10500' and the message was: 'None'”. The workbench still runs successfully in Form 2025.1 with no changes to the data.

The Portal writer is set to Use Existing and Insert and Truncate Existing. From other Community posts, it looks like the error I get is usually associated with a schema change, but there hasn’t been one here. Did something else change? We are running Portal 11.3.