My understanding of how AD Group and SP Group works with SharePoint permissions are:
- Adding a user or AD group to a SharePoint group or site causes a full index to calculate the permissions
- Adding users to an Active Directory group that already has permission in a SharePoint group does not trigger a full crawl of the index to calculate changes in permissions
If this problem occurred to be related to the second bullet above, then it may not work because no change in permissions is performed. If it is not, please open a support ticket with us.