Resolve error on deep insert of navigation property Dynamics WebAPI

I am using the Microsoft Dynamics Web API to write data to an entity in Microsoft Dynamics 365. When I try to do a deep insert I am receiving the error

An undeclared property 'ccseq_employeeid' which only has property annotations in the payload but no property value was found in the payload. In OData, only declared navigation properties and declared named streams can be represented as properties without values.

Why am I receiving this error and how can I resolve the error?

JSON

{
    "ccseq_importdate" : "2017-05-28T04:00:00Z", 
    "ccseq_month" : "1", 
    "ccseq_year" : "2017", 
    "ccseq_name" : "Test", 
    "ccseq_status" : "100000000", "ccseq_ccseq_expensetransactionset_ccseq_expensetransaction_ExpenseTransactionSetID" : 
    [ 
        { 
          "ccseq_employeeid@odata.bind": "/systemusers(6d2fd71b-32d1-dd11-a4f5-001a6449bbe7)", 
          "ccseq_clientid@odata.bind": "/ccseq_clients(663ebd00-73b9-4faf-90ed-f56bb9c2dc9b)", 
          "ccseq_navemployeeid" : "11111", 
          "ccseq_employeefirstname" : "John"
        }
    ]
}

ExpenseTransactionSet is the parent of ExpenseTransaction meaning that ExpenseTransaction has a lookup to ExpenseTransactionSet. ccseq_ccseq_expensetransactionset_ccseq_expensetransaction_ExpenseTransactionSetID is one to many relationship. systemuser and ccseq_clients are separate entities that are lookups in ExpenseTransaction.

I've also tried the below variations on the "ccseq_employeeid@odata.bind"

• objectid_systemuser@odata.bind
• objectid_ccseq_employeeid@odata.bind
• ccseq_employeeid@data.bind
• ccseq_employeeid@odata.bind : systemusers()
• ccseq_employeeid_systemusers@odata.bind
• systemuserid_systemusers@odata.bind

I have seen this question and this question and tried the suggested resolutions without success.

I discovered the answer reading this thread. The correct syntax for a Navigation Property in a deep insert is to use the Child Entity Name followed by brackets with the field name. The json needs to be changed to the below

{
    "ccseq_importdate" : "2017-05-28T04:00:00Z", 
    "ccseq_month" : "1", 
    "ccseq_year" : "2017", 
    "ccseq_name" : "Test", 
    "ccseq_status" : "100000000",
    "ccseq_ccseq_expensetransactionset_ccseq_expensetransaction_ExpenseTransactionSetID" : 
    [ 
        {
          // Next two lines are changed 
          "ExpenseTransaction[ccseq_employeeid@odata.bind]": "/systemusers(6d2fd71b-32d1-dd11-a4f5-001a6449bbe7)", 
          "ExpenseTransaction[ccseq_clientid@odata.bind]": "/ccseq_clients(663ebd00-73b9-4faf-90ed-f56bb9c2dc9b)", 
          "ccseq_navemployeeid" : "11111", 
          "ccseq_employeefirstname" : "John"
        }
    ]
}