Hyper-V Differencing Disks not processing when checkpoint is deleted.

I am having an issue on several of our servers where when Hyper-V checkpoints are deleted, the differencing disks are not merging. When I check the attached disk for the Hyper-V VM, it displays the differencing disk instead of the Hyper-V VM's VHD. Now, to make sure that the VHD folder for each VM on all of our servers, I made sure that the "NT VIRTUAL MACHINE\Virtual Machines" service account had the correct permissions by running the PowerShell command:

icacls "d:\VMs" /grant "NT VIRTUAL MACHINE\Virtual Machines:(OI)(CI)F"

After running that command, I ran:

Restart-Service vmms

When I stopped the affected VMs, on different servers, then the differencing disks processed. I have to do this whenever I need to process differencing disks.

We are utilizing Druva for our Hyper-V backup solution. And I also noticed that when Druva makes a backup, it utilizes Hyper-V checkpoints to do so. And those differencing disks are also not clearing out. Is this happening to anyone else? How can I fix this?