Can't select only one patrol in Report Builder

I am unable to select only one patrol for a Report Builder report without having to select the “Scouts not in a Patrol” grouping. If I attempt to save the report with one patrol selected and “Scouts not in a Patrol” unchecked, the saved report saves with “All Scouts” selected. The report will successfully save with one patrol selected as long as the “Scouts not in a Patrol” grouping is selected. Is this behavior by design?