An administrator is unable to unshare an item that is shared by the item’s owner to a group with access and update capabilities. The administrator is not a member of the group.
Use a second administrator account and become a member of the group and then change Sharing.
Add the administrator to the group through Organization > Edit Settings > Groups.
Search for the member and add to selected members. Click Next.
Search for the group and add the group to the ‘Selected group’ list. Click Next.
Verify the ‘Selected member’ and ‘Selected group’. Click Next.
Click on Done once finished.
Navigate to Manage Items for the first administrator by changing the Sharing settings.
Navigate to Organization. Click the Username for the first administrator > Manage Items
Share > Access and update capabilities. Note: If the group was created with group members as contributors this works. If the group was created with only group owner and managers then this workaround does not work.