vhdx on a csv keep getting securit permissions changed

Hi,

we have a cluster with csv disks, and DPM backup's those vm's with the client on the hypervysor

sometimes we get an error 

DPM encountered a retryable VSS error. (ID 30112 Details: VssError:The writer experienced a transient error.  If the backup process is retried,
the error may not reoccur.
 (0x800423F3))

we found out that something is changing the permissions of the VHDX files

and something is changing the permissions, is it possible that VMM is doing that?