[IgbTreeGrid] “Grid has no data” when a row without children follows a row with children

[TomoyaWashio]

Description

We observed an issue with IgbTreeGrid when the data source contains a mix of rows that have child collections and rows that do not. If a row without children is placed after a row that has children, the grid fails to render and only shows the message “Grid has no data.” However, if the order is reversed (childless rows first, then rows with children), the grid renders correctly.
Closes: https://infragistics.visualstudio.com/Indigo_Platform/_workitems/edit/41330

Steps to reproduce

1. Prepare an IgbTreeGrid with hierarchical data where some rows contain a children collection (e.g., children: [...]) and some rows have no children (e.g., children missing or empty).
2. Order the data so that at least one row with children is followed by a row without children.
3. Render the grid.

Result

When a row without children is placed after a row with children, the grid does not render and shows “Grid has no data.”

Expected result

The grid should render correctly regardless of the order of rows, even when the data source contains a mix of rows with and without children.

Attachments

C_00244985_BlazorServerApp1.zip