The Gris has incorrect layout when using kendoGridGroupHeaderColumnTemplate in combination with kendoGridDetailTemplate, which causes the group header column template to move with one cell to the left.

The Average: 19.47 aggregate should be under Unit Price column
To Reproduce
https://stackblitz.com/edit/angular-rpvoq5?file=app%2Fapp.component.ts
Fixed in the latest development build.
Fix released in v4.6.4