Multipart Form-Data Upload Fails with 'Cannot read properties of undefined (reading 'firstName')' in Tests Collection

[alireza-asgharii]

Description:
I’m experiencing an issue when trying to create a document in the tests collection via REST API using multipart/form-data to upload an image along with text fields (firstName, lastName, user). The request works fine when using JSON with just the media ID, but fails with the error Cannot read properties of undefined (reading 'firstName') when I send a file directly.

Steps to Reproduce:

1. Set up a tests collection with the following configuration:

   import { type CollectionConfig } from "payload";
   
   export const Tests: CollectionConfig = {
     slug: "tests",
     fields: [
       { name: "firstName", type: "text" },
       { name: "lastName", type: "text" },
       { name: "user", type: "relationship", relationTo: "users" },
       { name: "image", type: "upload", relationTo: "media", required: true },
     ],
   };
   
   

*** I have this collection and I want to make a post request with the api/test path.
I did the test in my postman:
1- Body: If I send the data in the body format, i.e. as follows, the request is done correctly (in this method, the file is uploaded first and its ID is placed in the request)
{
"lastName": "test new",
"firstName": "me",
"image": "67bed87ed05f4b76c53e2bde"
}

2- form-data: If I want to send the request in the multiform method, i.e. send the file, the server side returns an error:

Req:

err:
Cannot read properties of undefined (reading 'firstName')

Does the payload have a method for what I want (sending a file to the desired collection) or not?