UI-Grid grouping: Extra blank rows getting displayed when a row is expanded

Hi, I am facing a weird issue. When I group by 4 or more columns, and then expand a row, then extra blank rows show up. Even more weird thing is that on collapsing and expanding the parent row again, some of these blank rows disappear. I have searched for this issue extensively, but I did not find any help. We are fetching the data though a remote REST API call. I can attach the screenshot of the problem. We are simply using the group by feature of the ui-grid. Please feel free to get back to me if you need any more information.