When a report has the Group By feature enabled, it does not show correctly when used in a portal section. When running the report itself, the rows that are grouped will have the similar fields omitted, except for the first occurrence of those fields, which is the expected behavior. However, when using the same report in a portal section, it doesn’t do that; all similar fields grouped still shows. Therefore, it is difficult for the user to catch which records are grouped or not.
The logic used in queries in portals needed to be updated to resolve the issue. Moving forward, portal sections can now render report results that have a “Group By” feature added in their queries.