I know that for VMware, we need to pass start: "1", like this:
compute_attributes:
start: "1"
Might be worth trying? Last time I came close to a Proxmox installation was 2014, so I am purely guessing here 
I know that for VMware, we need to pass start: "1", like this:
compute_attributes:
start: "1"
Might be worth trying? Last time I came close to a Proxmox installation was 2014, so I am purely guessing here 