Update Azure function to isolated worker model gives 'FUNCTIONS_WORKER_RUNTIME' warning

I have updated an Azure function app from the in process model to the Isolated worker model but get this warning message in the portal.

The 'FUNCTIONS_WORKER_RUNTIME' setting is required. Please specify a valid value. See https://go.microsoft.com/fwlink/?linkid=2257963 for more information. The application will continue to run, but may throw an exception in a future release.

I have added the required application setting but it doesn't resolve.

My function app works as expected but just see this warning message in the portal.

This warning occurs if the Azure function app is not able to detect the expected configuration for the function runtime i.e., if Function app's host is unable to determine the correct language or language runtime stack.

To resolve this,FUNCTIONS_WORKER_RUNTIME is a required setting, set it explicitly in all of the existing function apps to prevent any downtime. when running the function locally, add the setting in local.settings.json, and under environment variables in portal.

local.settings.json:

{
    "IsEncrypted": false,
    "Values": {
        "AzureWebJobsStorage": "UseDevelopmentStorage=true",
        "FUNCTIONS_WORKER_RUNTIME": "dotnet-isolated"
    }
}

Check if you have multiple FUNCTIONS_WORKER_RUNTIME settings added in the function app's App Settings.

After adding FUNCTIONS_WORKER_RUNTIME in the Function app=>Environment variables, restart the Function App to ensure changes reflects.

• Go to the "Overview" section of your Function App and click on "Restart".