When I have array in json data, that holds 21 rows with 3 diffrent types of "AssetTypeName" (column) which is the column that the grid is groupped by, it will result in a grid that shows the same group multiple times. The only group that appears one time is a group that has only one row in that particular AssetTypeName category.
For example AssetTypeName = "Domestic bonds" should have 5 rows but the grid shows the groups three times which all contains the same 2 first rows in that category.
When I expand some group-row, all the duplicated groups will expand.
here is a example that replicates this issue:
[http://plnkr.co/edit/fBqNq33XmQTYS4Ga9wrW?p=preview][1]
Sincerly - aghaux