Internal exception for missing files in form data

[EliasGit117]

export class FormDataTestDto {
  @IsInt()
  @ApiProperty({ example: "1" })
  @Transform(({ value }) => Number(value))
  id: number;

  @IsFile()
  @HasMimeType(['text/plain'])
  @ApiProperty({ type: "string", format: "binary", required: false })
  @MaxFileSize(5)
  @MinFileSize(3)
  @IsOptional()
  file?: MemoryStoredFile;
}

If there is no file provided in form data I get error:

[00:29:29.937] ERROR (46218): Multipart: Boundary not found {"req":{"id":"req-3","method":"POST","url":"/auth/test-form-data"},"context":"ExceptionsFilter"}
    err: {
      "type": "Error",
      "message": "Multipart: Boundary not found",
      "stack":
          Error: Multipart: Boundary not found
              at new Multipart (/Users/eliassmith/Dev/Projects/bazaar-be/node_modules/busboy/lib/types/multipart.js:233:13)
              at getInstance (/Users/eliassmith/Dev/Projects/bazaar-be/node_modules/busboy/lib/index.js:33:12)
              at module.exports (/Users/eliassmith/Dev/Projects/bazaar-be/node_modules/busboy/lib/index.js:56:10)
              at new FormReader (/Users/eliassmith/Dev/Projects/bazaar-be/node_modules/nestjs-form-data/src/classes/FormReader.ts:22:25)
              at FormDataInterceptor.intercept (/Users/eliassmith/Dev/Projects/bazaar-be/node_modules/nestjs-form-data/src/interceptors/FormData.interceptor.ts:51:36)
              at nextFn (/Users/eliassmith/Dev/Projects/bazaar-be/node_modules/@nestjs/core/interceptors/interceptors-consumer.js:23:36)
              at /Users/eliassmith/Dev/Projects/bazaar-be/node_modules/@nestjs/core/interceptors/interceptors-consumer.js:21:88
              at AsyncResource.runInAsyncScope (node:async_hooks:213:14)
              at bound (node:async_hooks:244:16)
              at Observable._subscribe (/Users/eliassmith/Dev/Projects/bazaar-be/node_modules/rxjs/src/internal/observable/defer.ts:54:15)
    }

[EliasGit117]

Update: it happens only if I pass in form data "file" nothing