Running the 'solve' operation in a service area with the option to allow overlapping polygons creates a different polygon than if overlapping is not allowed, even when there is only one point.
Last Published: August 24, 2015ArcGIS for Desktop
Bug ID Number
August 15, 2015
September 24, 2021
ArcGIS for Desktop
After review by the development team, it has been determined that this issue is related to a known limitation with the software that lies outside of Esri's control. The issue's Additional Information section may contain further explanation.
This is as designed. These options work differently to generate service area polygons so some differences is to be expected.