{
    "type": "sdfsdfsdfsd",
    "title": "One or more validation errors occurred.",
    "status": 400,
    "traceId": "sdfsdfsdfsdf",
    "errors": {
        "requestForm": [
            "The requestForm field is required."
        ],
        "$.whencalculated": [
            "The JSON value could not be converted to System.Nullable`1[System.DateTime]. Path: SENSITIVE DATA"
        ]
    }
}

{
    "type": "sdfsdfsdfsd",
    "title": "One or more validation errors occurred.",
    "status": 400,
    "traceId": "sdfsdfsdfsdf",
    "errors": {
        "requestForm": [
            "The requestForm field is required."
        ],
        "$.whencalculated": [
            "The JSON value could not be converted to System.Nullable`1[System.DateTime]. Path: SENSITIVE DATA"
        ]
    }
}

"xxController.cs":
namespace xx.Controllers
{
  [ApiController]  // it is an option to remove this to be able to parse the body properly (see: https://stackoverflow.com/questions/60071028/invalid-model-class-property-error-in-net-core-api)
  [Produces("application/json")]
  [Route("xx/api/[controller]")]
  [PostBodyFilterAttribute("xxController")]
  public class xxController : Controller
  {
        [HttpPost]
        public async Task<ActionResult<ResponseFormDto>> PostTodoItem([FromBody]RequestFormDto requestForm)
        {   
            // DOES NOT REACH THIS PART
            try
            { ....
            
"RequestFormDto.cs"
public class RequestFormDto
  {
        [JsonPropertyName("whencalculated")]
        public DateTime? WhenCalculated {
      get;
      set; }
      ....
      

"xxController.cs":
namespace xx.Controllers
{
  [ApiController]  // it is an option to remove this to be able to parse the body properly (see: https://stackoverflow.com/questions/60071028/invalid-model-class-property-error-in-net-core-api)
  [Produces("application/json")]
  [Route("xx/api/[controller]")]
  [PostBodyFilterAttribute("xxController")]
  public class xxController : Controller
  {
        [HttpPost]
        public async Task<ActionResult<ResponseFormDto>> PostTodoItem([FromBody]RequestFormDto requestForm)
        {   
            // DOES NOT REACH THIS PART
            try
            { ....
            
"RequestFormDto.cs"
public class RequestFormDto
  {
        [JsonPropertyName("whencalculated")]
        public DateTime? WhenCalculated {
      get;
      set; }
      ....