Microsoft.Web/sites resource provider return an InternalServerError status when integrating Managed Service Identities

Question

After seeing the article here about integrating Managed Service Identities (MSI) with Azure AppService I wanted to give it a try.

I have inserted the new identity member inside my Microsoft.Web/sites resource like instructed in the article.

"identity": {
  "type": "SystemAssigned"
}

But now when I deploy the template, my web apps are failing with the following error:

{
  "error": {
    "code": "ResourceDeploymentFailure",
    "message": "The response for resource had empty or invalid content."
  }
 }

The resource seems to deploy fine and MSI is now activated but I have this error and it failed my template deployment.

I have tested the deployment for this resource type using apiVersion 2016-03-01 & 2016-08-01 and I get the same error.

Thanks in advance