Bug: Expanding groupBy in a subGrid not display correctly

I attach 3 photos: before and after expanding GroupBy in a SubGrid, and a working one (where I do not collapse all on subgrid load).

You can see that expanding GroupBy content lay on top of other rows in a parent grid , instead of pushing down like the photo of Working Subgrid.

Unfortunately the issue cannot be reconstructed.
Please, provide a sample of your code