Calling Azure Function from ADF with Route Path Implementation Fails

I am trying to call an Azure Function from ADF. Azure Function has Route implemented as shown below.

[FunctionName("UpdateStatus_V1")]
public static async Task<IActionResult> Run([HttpTrigger(AuthorizationLevel.Function, "post", Route = "V1/UpdateStatus")] HttpRequest req, ILogger log)

Also the host file has a routePrefix in Azure Function

"http": {
  "routePrefix": "DeltaAPI"
}

URI on the Function APP appears as below.

https://functionAPP.azurewebsites.net/DeltaAPI/V1/UpdateStatus?code=secret

When i try to invoke this function from Azure Data Factory using a Function Activity - I keep getting this error

{ 
   "errorCode":"3608",
   "message":"Call to provided Azure function '' failed with status-'NotFound' and message - 'Invoking Azure function failed with HttpStatusCode - NotFound.'.",
   "failureType":"UserError",
   "target":"Azure Function1"
}

I have followed the recommendation as per document https://docs.microsoft.com/en-us/azure/data-factory/control-flow-azure-function-activity#routing-and-queries and the adf pipeline code is given below:

{
  "name": "FunctionTest",
  "properties": {
    "activities": [
      {
        "name": "Azure Function1",
        "type": "AzureFunctionActivity",
        "dependsOn": [],
        "policy": {
          "timeout": "7.00:00:00",
          "retry": 0,
          "retryIntervalInSeconds": 30,
          "secureOutput": false,
          "secureInput": false
        },
        "userProperties": [],
        "typeProperties": {
          "functionName": "V1/UpdateStatus",
          "method": "POST",
          "headers": {
            "Content-Type": "application/json"
          },
          "body": {
            "value": "@json( '{\n \"transactionid\": \"5d283e11e62943ceb2e6e0bb5fe4898f\",\n \"status\": \"Completed\",\n \"Description\": \"\"\n }')",
            "type": "Expression"
          }
        },
        "linkedServiceName": {
          "referenceName": "AzureFunction",
          "type": "LinkedServiceReference"
        }
      }
    ],
    "annotations": []
  }
}