I misunderstood the original problem (lack of sleep).
Can you post your entire workflow? That way I can see where it is going wrong? I am sure I know what the issue is but need to confirm and figure a way around it.
Problem (assumption at this point):
The "vm" variable is used to indicate the clone template but then kept when passed to the additional disk workflow. So essentially to both workflows, the "vm" variable = clone & new vm
Thanks
B