existing BIG-IP destroyed/recreated when count is incremented

[mjmenger]

When incrementing the count value on the module after a successful terraform apply and running a subsequent terraform apply the existing BIG-IPs are destroyed and recreated.

module bigip {
  count                      = 2
  source                     = "F5Networks/bigip-module/azure"
  version                    = "1.1.1"
...
}

Expected Result:

When count is increased, the necessary additional BIG-IPs are created and any existing BIG-IPs are left unchanged.

Actual Result:

When increasing count from 1 to 2 the initial BIG-IP (index 0) is destroyed and then recreated.

module.bigip[1].azurerm_virtual_machine.f5vm01: Still creating... [30s elapsed]
module.bigip[0].azurerm_virtual_machine.f5vm01: Still destroying... [id=/subscriptions/...
...
module.bigip[0].azurerm_virtual_machine.f5vm01: Still creating... [50s elapsed]

[mjmenger]

After two applies that exhibited this behavior, I have not been able to recreate this issue. I will close the issue.