Input validation through oneOf does not work if no element matches.

[nappalm]

I am sending a POST request to create items; however, the submission options tend to vary based on the reportType property. Since I stopped using Joi and switched to express-openapi-validator, could you help me validate if reportType = "item1" then the requestBody must match item1.requestBody?

post:
  requestBody:
    content:
      application/json:
       schema:
        oneOf:
         - $ref: "./requestBody/item1.requestBody.yaml"
         - $ref: "./requestBody/item2.requestBody.yaml"
         - $ref: "./requestBody/item3.requestBody.yaml"

Request Body:
item1.requestBody.yaml:

type: object
properties:
  reportType:
    $ref: "../../../commons/schemas/reportType.schema.yaml"
  age:
    type: integer
    example: 20
required:
  - reportType
  - age

---

item2.requestBody.yaml:

type: object
properties:
  reportType:
    $ref: "../../../commons/schemas/reportType.schema.yaml"
  name:
    type: string
    example: "Example name"
required:
  - reportType
  - name

Actually, when the data matches a schema, it does validate the type. However, if I try to send:

{
 reportType: "item1"
}

The request goes through without any issues since it does not match any requestBody. Has anyone encountered a similar problem where the input type to validate depends on a property? If so, what would you recommend?

UPDATE:
I have added a discriminator and it still didn't work.

post:
  requestBody:
    content:
      application/json:
        schema:
          discriminator:
            propertyName: reportType
            mapping:
              item1: "./requestBody/item1.requestBody.yaml"
              item2: "./requestBody/item2.requestBody.yaml"
          oneOf:
            - $ref: "./requestBody/item1.requestBody.yaml"
            - $ref: "./requestBody/item2.requestBody.yaml"