OpenAPI V3 Maven Plugin generates incomplete interface code with multiple file upload using multipart/form-data

Question

I am using Openapi V3 with Maven plugin openapi-generator-maven-plugin (5.3.0) for multiple files upload with multipart/form-data. However, the interface code generated is incomplete - missing List declaration in one of the default method (One method declares input parameter as List<MultipartFile> file and the other method declares it as MultipartFile file):

default ResponseEntity<UploadDocumentsResponse> _uploadDocuments(@Valid @RequestPart(value = "file", required = false) List<MultipartFile> file) {
        return uploadDocuments(authorization, file);
    }

    // Override this method
    default  ResponseEntity<UploadDocumentsResponse> uploadDocuments(MultipartFile file) {
...
}

Here is the spec:

/api/uploadDocuments:
    post:
      tags:
        - documents
      summary: Upload documents
      description: Upload documents
      operationId: uploadDocuments
      requestBody:
        required: true
        content:
          multipart/form-data:
            schema:
              type: object
              properties:
                file:
                  type: array
                  items:
                    type: string
                    format: binary