Post operation of creating user with Trips failing

We are from Adobe System part of the AEM Forms Product team.
We were trying to make use of your APIs for an internal PoC.

We are using HTTP requests :
https://www.odata.org/getting-started/understand-odata-in-6-steps/

In the process we encountered some trouble.
When we try to submit user details along with trip data, the POST call fails. It doesn’t accept the key ‘Trips’ in the Request body of the object.

However, when we do a GET to retrieve existing data, we are able to see the key ‘Trips’, with value populated under it.

sample request for post people/person
{
"Person": {
"UserName": "test159",
"FirstName": "qui Excepteur eiusmo",
"LastName": "ametullamco in",
"Emails": [
"veniam incidid",
"deserunt dolore"
],
"Gender": "Male",
"AddressInfo": [
{
"Address": "cupidatat anim",
"City": {
"CountryRegion": "deserunt",
"Name": "sint magna cup",
"Region": "sedex"
}
}
],
"Trips": [
{
"TripId": 561,
"Tags": [
"idani",
"anim sunt ei",
"consect"
],
"ShareId": "Excepteur",
"Description": "officia",
"Name": "irure Ut ad consectet",
"Budget": 13
},
{
"TripId": 663,
"Tags": [
"idani",
"anim sunt ei",
"consect"
],
"ShareId": "Excepteur1",
"Description": "officia 1",
"Name": "irure Ut ad consectet 11",
"Budget": 136
}
]
}
}

Reproduce the POST to people/person using the request body shown, then compare it with the GET representation that includes Trips. Capture the response or error and determine whether nested Trips is supported; done means the supported request behavior is documented or the POST accepts the intended payload.