After tracing, i creat a basic diagram.
And i tried to store the diagram.
The GPtool works successfully, and the diagram shows in catalog.
But i can't use the Find Diagram in Utility Network tab to find the diagram.
And if i close the Diagram map, it will also disappear in catalog like it's still temporary.
Using ArcGIS Pro 3.1 the Utility Network is build in file geodatabase.