Hyper-V CBT, Job shows warning "Failed to flush change tracking data"

Job could report warning "Failed to flush change tracking data for VM {$VMNAME}"
In the logs you could see:

[20.12.2012 23:45:29] <10> Error    The request is not supported.\n\nFailed to add file 'U:\Inventory\Inventory.vhd' to the list of CTP tracked items.\n
--tr:Failed to add file 'U:\Inventory\Inventory.vhd' to the list of CTP tracked items. VM: 'Inventory'. VmID: '{b2abace9-d782-4393-b7b4-84c2ba0b0f9d}'.\n
Failed to add file to change tracking.\nArguments:  (Veeam.Backup.Common.CAppException)
...
[20.12.2012 23:45:29] <10> Error    [Inventory]  Failed to flush change tracking data for VM Inventory before snapshot.
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