New channel experience breaks task module from 3rd party app

Meghana-MSFT 
I have another variant that is not working. When you get to open a URL based task module (which sometimes works and sometimes don't) and in the task module the code uses

`dialog.url.submit` and the server response with another continue to load a further task module,:

{
  "task": {
    "type": "continue",
    "value": {
      "title": "Render webpage II",
      "height": 415,
      "width": 600,
      "url": "https://local.example.com/testDialog2",
      "fallbackUrl": "https://local.example.com/testDialog2"
    }
  }
}

then the task dialog changes the size but not loads the content from the new URL. 
This works fine on the old experience and e.g. in the mobile client. So it is related to the new channel experience.