(Hyper-V 2019) New-VHD command fails to convert virtual disk

Hi all,

The following commands work on Hyper-V Server 2012R2 and 2016:

Mount-VHD -Path "D:\Hyper-V\Virtual Hard Disks\test.vhdx" -ReadOnly -Passthru
New-VHD -SourceDisk 2 -Path "D:\Test\new-disk.vhdx" -Dynamic

but on Hyper-V Server 2019 I get the following error:

New-VHD : Failed to convert the virtual disk.
The system failed to convert
'\\?\scsi#disk&ven_msft&prod_virtual_disk#2&1f4adffe&0&000003#{53f56307-b6bf-11d0-94f2-00a0c91efb8b}'.
Failed to convert the virtual disk.
The system failed to convert
'\\?\scsi#disk&ven_msft&prod_virtual_disk#2&1f4adffe&0&000003#{53f56307-b6bf-11d0-94f2-00a0c91efb8b}': Incorrect
function. (0x80070001).
At line:1 char:1+ New-VHD -Path "D:\Test\new-disk.vhdx ...+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~+ CategoryInfo          : NotSpecified: (:) [New-VHD], VirtualizationException+ FullyQualifiedErrorId : OperationFailed,Microsoft.Vhd.PowerShell.Cmdlets.NewVhd

The disk is attached to a Gen 1 VM and there are no checkpoints associated with it. Not quite sure what the problem is.