Some tools (Con, IsNull) do not output results, which are successful.
Last Published: January 13, 2017ArcGIS for Desktop
Bug ID Number
December 22, 2015
March 30, 2022
ArcGIS for Desktop
Will Not Be Addressed
The development team has considered the issue or request and concluded it will not be addressed. The issue's Additional Information section may contain further explanation.
This is by design.
The behavior of Focal Statistics is different with that of Con and SetNull when using arcpy.sa, because the inside execution of these tools are different.
When running some tools such as arcpy.sa.Con() and arcpy.sa.SetNull(), they are acting like python behavior, and would have no tool execution history. While, tool such as arcpy.sa.FocalStatistics(), acts the same as geoprocesing tool, so it will have a result history. So if you use arcpy.gp.Con_sa() instead of arcpy.sa.Con(), it will act like the geoprocessing tool, and will have result history.