The ArcGIS Pro Spatial Join tool fails to maintain the Field Map parameter configuration when revalidating the model tool after a successful execution.
Tested in ArcGIS Pro 3.5, customizing the Spatial Join Field Map parameter in the model is maintained after running and revalidating. Also tested saving and closing, reopening, and revalidating, and the customized field maps for all Spatial Join tools in the model are the same as previously saved (they were not reset after running or validating).