How to determine the tombstonelifetime ?
Please run this on the domain controller to determine your tombstonelifetime.
Please change the ForestRootDN for your domain
dsquery * "cn=Directory Service,cn=Windows NT,cn=Services,cn=Configuration,dc=<ForestRootDN>" -scope base -attr tombstonelifetime
By default, an object's tombstone is deleted from Active Directory 60 days after the object itself is deleted. Starting in Windows Server 2003 Service Pack 1, the default tombstone interval has been changed to 180 days, but only for new deployments of Active Directory.