Serialize nested properties as form-data with swagger-php

I have this code and recommended is sent as string. Swagger-php doesn't properly serialize nested objects as form-data.

 *     @OA\RequestBody(
 *          @OA\MediaType(
 *              mediaType="multipart/form-data",
 *              @OA\Schema(
 *                  @OA\Property(
 *                      property="name",
 *                      title="name",
 *                      type="string",
 *                      description="Name"
 *                  ),
 *                  @OA\Property(
 *                      property="recommended",
 *                      type="object",
 *                      @OA\Property(
 *                          property="size",
 *                          type="string",
 *                          description="Storage capacity"
 *                      ),
 *                      @OA\Property(
 *                          property="memory",
 *                          type="string",
 *                          description="Memory size"
 *                      )
 *                  )
 *              )
 *          )
 *     )

from Serialize nested properties as form-data with swagger-php