Lock file error when importing resource in terraform

Question

I'm trying to import 2 existing azure resources (1 vnet and 1 resource group).

If I add the following to my main.tf

resource "azurerm_virtual_network" "my-vnet" {
}

and run terraform import azurerm_virtual_network.my-vnet /subscriptions/11111111/resourceGroups/my-resource-group/providers/Microsoft.Network/virtualNetworks/my-vnet-01

Everything works perfectly, the terraform.tfstate file gets updated with the vnet information etc.

If I then add the following to the main.tf

resource "azurem_resource_group" "my-net-rsg" {
}

and run terraform import azurem_resource_group.my-net-rsg /subscriptions/11111111/resourceGroups/my-net-rsg

I get the following error

If I then remove

resource "azurem_resource_group" "my-net-rsg" {
}

and run the same terraform import azurem_resource_group.my-net-rsg /subscriptions/11111111/resourceGroups/my-net-rsg I get an error (quite rightly & expectedly) saying

Before importing this resource, please create its configuration in the root module. For example:  

resource "azurem_resource_group" "my-net-rsg" {
# (resource arguments)
}

Even if I literally copy and paste that output back into my main.tf file I get the same error from the screen shot above.

I've tried only having the resource group config
I've tried having the resource config first before the vnet
I've tried a fresh terraform init in a different directory and walking through the process again.

Every time if I have the resource group in the main.tf it complains about the lock file.