cloud-init ip config is lost when changing CPU or memory in a cloned VM

[b4stien]

Describe the bug

When changing the CPU's core count or memory amount the IP config is lost in cloud-init thus resulting in a loss of network for the VM after the change.

EDIT: If it's relevant, changing the core count or the memory amount in the interface do not impact cloud-init (thus not producing the bug).

EDIT2: Other info, if I put user account info in cloud-init, it is preserved after the CPU/memory changes.

To Reproduce

1. Create a VM with 4 cores, and an IP config.
2. Observe that the IP config is available in Proxmox UI and the QEMU guest agent export the IP to the Proxmox UI (and the TF provider).
3. Modify the core count.
4. Observe that the IP config is gone in Proxmox UI and that the VM no longer has network access.

VM creation

resource "proxmox_virtual_environment_vm" "proxmox_vm" {
  name = "simple-vm-via-opentofu"
  node_name = "proxmox"

  agent {
    enabled = true
  }

  started = true

  cpu {
    cores = 8
  }

  clone {
    full = true
    vm_id = 667
    node_name = "proxmox"
  }

  initialization {
    ip_config {
      ipv4 {
        address = "dhcp"
      }
    }
  }

  stop_on_destroy = true
}

IP config is correct

VM modification

resource "proxmox_virtual_environment_vm" "proxmox_vm" {
  name = "simple-vm-via-opentofu"
  node_name = "proxmox"

  agent {
    enabled = true
  }

  started = true

  cpu {
    cores = 4
  }

  clone {
    full = true
    vm_id = 667
    node_name = "proxmox"
  }

  initialization {
    ip_config {
      ipv4 {
        address = "dhcp"
      }
    }
  }

  stop_on_destroy = true
}

IP config is gone

Additional context

• Single or clustered Proxmox: Single
• Proxmox version: 9.3
• Provider version (ideally it should be the latest version): 0.69.1
• Terraform/OpenTofu version: OpenTofu v1.8.8
• OS (where you run Terraform/OpenTofu from): macOS 15.2