After items have been inserted at runtime in a DataGrid that uses grouping, visual glitches occur and upon tapping an exception is being thrown. The visual glitches may include an item overlapping a group header; missing items; duplicated items. Upon tapping an incorrectly drawn group header, an exception is thrown. 

Available in minor release 2017.3.1214. It will also be available in the R1 2018 release.