MS Gantt not rendering in Service with all tasks grouped by parent. Works fine in Desktop.

[CDE]

In my MS Gantt visual, I grouped all tasks by their parent, and it works as expected in Power BI Desktop. However, when I publish the report to the Power BI Service, only the Legend and a horizontal line are visible. If I edit the report in the Service and toggle the "Group Tasks" option off and back on, the Gantt visual displays correctly. After saving and closing the browser, though, the issue returns when I reopen the report, showing only the Legend and nothing else.

To troubleshoot, I downloaded the MS Gantt sample from AppSource, assigned a parent to all tasks, enabled grouping, and published it. The same issue occurred in the Service: only the Legend was visible. Interestingly, when I left some tasks unassigned to a parent and grouped the others, the Gantt visual worked as intended. It displayed expandable/collapsible groups for the grouped tasks and included the tasks without a parent. The problem seems to occur only when all tasks are grouped, preventing the visual from rendering correctly in the Power BI Service.