REST timeEventRequests always encounter "Unable to parse the provided payload"

Summary:

When I try to create a time event by using timeEventRequests I always encounter "Unable to parse the provided payload". I am using the call from here

POST /hcmRestApi/resources/11.13.18.05/timeEventRequests

Content (please ensure you mask any confidential information):

Version (include the version you are using, if applicable):

Code Snippet (add any code snippets that support your topic, if applicable):
(ORACLE DELIVERED FROM THE SUPPORT PAGE)
{

    "required":[

        "requestNumber",

        "requestTimestamp",

        "sourceId"

    ],

    "type":"object",

    "properties":{

        "sourceId":{

            "maxLength":"40",

            "type":"string",

            "description":"Unique identifier for the source creating the data, for example, supplier name or facility identifier.",

            "nullable":false

        },

        "requestNumber":{

            "maxLength":"80",

            "type":"string",