Report 'Record Count' Changes when 'Details' are Hidden or Exposed

When report columns are hidden ('Show Details' is disabled) and the report does not contain references to any parent or child of the target Object of the report (for examples: filters, summaries, groupings), then any requirement of that relationship defined at the Report Type level is ignored.

Example Scenario

Scenario: You create a report on the Opportunities Object and select to display specific columns from the Accounts and Opportunities Objects.

Reports require that the displayed results possess relationships between all of the objects that have columns displayed on the report.

By adding columns from the 'Accounts' Object to an Opportunities Object report, you have mandated that any records displayed within the report's results be associated with an Account record.

If you hide the details of this report and do not update your report references (filters, summaries, groupings) to capture this requirement when the details are hidden, then the requirement that an Account be defined is ignored.

Additional Notes

• This behavior does not occur for the 'With or Without' relationship dynamic available with Custom Report Types, however Objects within Custom Report Types relying on the traditional 'With' relationship are still impacted.
• Records not associated with the Objects referenced by a report's columns will not appear on the report. Removing the columns that reference other Objects will not change this behavior or add the 'missing' records to the report.