Could you try setting the GroupLoadMode
property of the grid MasterTableView to Client
and see if it makes any difference? In this case you might also set the AllowGroupExpandCollapse
property in the grid ClientSettings to true
If the issue persists, I suggest that you send us a runnable sample illustrating your scenario and the issue you are facing. Thus I could debug it in depth locally in order to find a resolution for you.
All the best,
the Telerik team