Saved report hierarchy changes when report is run by a Partner or Community User

When an external user views a report with a saved hierarchy level, the report will run at the saved hierarchy level in instances when the external viewing user's role is in direct lineage with the saved role.  
However, if the external viewing user's role is not in direct lineage with the selected role, the report will default to display data at the external viewing user's role.  

For instance, if your role hierarchy is as follows (where the Sales Team, Marketing Team, and HR Department are all sibling roles): 

ADMIN/CEO
     President
          Sales Team
          Marketing Team
          HR Department

and the report is saved at the "Marketing Team" level, external users who report to a user within the "Sales Team" role will view the report at their own level in the role hierarchy.  But, if the report had been saved at the "Sales Team", "President" or "ADMIN/CEO" role, external users who report to a user within the "Sales Team" role will view the report at the saved hierarchy level.