Pre-expand table rows

Is there any way to expand data grid rows when the grid renders? Currently I can see there is the Grid.ExpandRow function which I call in an OnAfterRenderAsync functioni based on my data model like so:

The issue I have is that after the rows are expanded, they immediately collapse back. I am unsure right now what causes this in my code, but I was hoping that being able to specidy in the RowRender args if a row is pre expanded could fix this issue.

ExpandRow() is the only possible approach and it's demonstrated on our hierarchical demos: