I'm sending a POST request to create a record on CQ with all the mandatory fields as part of the request and still getting back an error saying "CRVAP0290E CRMUD0061E The field "DeploymentUnit_Form" is mandatory; a value must be specified".

Here is my request
POST https://xxxxxxx/cqweb/oslc/repo/9.0.0/db/MSG2/record
Accept: application/json
OSLC-Core-Version: 2.0
Content-Type: application/json
Authorization: Basic xxxxxxxxxxxxxxxxxxxxx
{
  "prefixes":{
    "cq":"http://www.ibm.com/xmlns/prod/rational/clearquest/1.0/",
    "dcterms":"http://purl.org/dc/terms/",
    "oslc":"http://open-services.net/ns/core#",
    "oslc_cm":"http://open-services.net/ns/cm#"
  },
  "dcterms:type":"DeliveryNote",
  "cq:Supplier":"WebApp",
  "cq:Application":"WebCSC",
  "cq:KDGContact":"xxxxx",
  "cq:SupplierContact":"xxxxxx",
  "cq:AppVersion":"V1530_2017_05_00",
  "cq:Patch":"Frontend (2017_05)",
  "cq:TargetPlatform":"Linux",
  "cq:PackageType":"Standalone Patch",
  "cq:Comment":"Test",
  "cq:DeploymentUnit_Form":"Server"
}

Here is the response
409
Transfer-Encoding: chunked
Keep-Alive: timeout=10, max=100
Connection: Keep-Alive
Date: Fri, 17 Mar 2017 14:53:33 GMT
OSLC-Core-Version: 2.0
X-Frame-Options: SAMEORIGIN
Cache-Control: no-cache="set-cookie, set-cookie2"
Set-Cookie: JSESSIONID=xxxxxxxxxxxxxxxxxxxxxxxxxxxx
Vary: Accept
Expires: Thu, 01 Dec 1994 16:00:00 GMT
Content-Language: de-DE
Content-Type: application/json; charset=UTF-8
X-Powered-By: Servlet/3.0
{
  "oslc:message":"CRVAP0290E CRMUD0061E The field \"DeploymentUnit_Form\" is mandatory; a value must be specified. ",
  "oslc:statusCode":"409",
  "oslc:url":{
    "rdf:resource":"https:\/\/xxxxxxxx\/cqweb\/oslc\/repo\/9.0.0\/db\/MSG2\/record-type\/16781099\/creationDialog",
    "oslc:rel":"alternate",
    "oslc:hintWidth":906,
    "oslc:hintHeight":779
  },
  "details":{
    "invalidFields":{
      "DeploymentUnit_Form":{
        "message":"CRMUD0061E The field \"DeploymentUnit_Form\" is mandatory; a value must be specified.",
        "currentValue":""
      },
      "AppVersion":{
        "message":"CRMUD0061E The field \"AppVersion\" is mandatory; a value must be specified.",
        "currentValue":""
      }
    }
  }
}


We face this issue since upgrade CQ to 9.0.0
It was working in Version 7.1.2

Could you kindly tell me where am i going wrong?

Disaclaimer: I would like to use pre-formatted code as example but then it always complains about SPAM...