Microsoft Planner @Mention and Comment Notification in Microsoft Teams - NEW VERSION

I'm still trying to get this to work. I've been able to resolve all the errors along the way, but now am left with a "Bad Request" error for the last function "Post Card in Chat or Channel" I'm not able to find out what is wrong. Here is the output:

{
  "error": {
    "code": 400,
    "message": "Card body contains invalid json characters(s): Message After parsing a value an unexpected character was encountered: :. Path 'body[1].text', line 40, position 29.",
    "source": "flow-apim-msmanaged-na-eastus2-01.azure-apim.net",
    "path": "choose[14]\\when[1]\\choose\\otherwise",
    "policyId": "",
    "clientRequestId": "a848ea29-eff6-4abf-8ede-ac5ab42ecd06",
    "dreeSet": "true"
  }
}