If you MOVE a Hyper-V Virtual Machine to Server 2012 R2 host and you want to move it back, you will be disappointed. Moving VM’s to Server 2012 R2 hosts is a one way street. This includes trying to move VM’s from Server 2012 R2 to 2012 R1.
Moving a Hyper-V virtual machine in Windows Server 2012 R2 to Hyper-V in Windows Server 2012 is not supported.
When moving a virtual machine on Windows Server 2012, the specified destination server can now be a computer running Windows Server 2012 R2. This applies to a move that is initiated in Hyper-V Manager or when using the Move-VM Windows PowerShell cmdlet.
… and don’t think that you can EXPORT the VM from Server 2012 R2 and IMPORT it into Server 2012 R1 ’cause you can’t. If you try you will see OPERATION FAILED WITH ERROR CODE ‘32784’, which Microsoft translates to THIS TechNet article.
The only easy way around this is to copy the VHDX from the Server 2012 R2 host, to the Server 2012 R1 host and recreate the VM using that disk.