Azure Functions not showing all executions under Monitoring

After lodging a support ticket with Microsoft, it seems that you also need to explicitly disable sampling in your hosts.json file for the Function App. The logging snippet below needs to be added to your hosts.json file prior to deployment. After adding this and re-deploying, all executions of this function have appeared.

{
  "version": "2.0",
  "logging": {
    "applicationInsights": {
      "samplingSettings": {
        "isEnabled": false
      }
    }
  }
}