File upload fails with `byte[]` or `InputStream` due to requiring filename

I am trying to upload a file using the OpenAI Java SDK and encountered an issue where the request fails when using InputStream, but succeeds when using Paths.get().

Use Code

public String uploadFile(MultipartFile file) {
    FileCreateParams params = FileCreateParams.builder()
                                              .file(file.getInputStream()) // Using InputStream
                                              .purpose(FilePurpose.ASSISTANTS)
                                              .build();

    FileObject fileObject = openAIClient.files().create(params);

    return fileObject.id();
}

When using InputStream, the following error occurs:

400: OpenAIError{additionalProperties={error={message=The browser (or proxy) sent a request that this server could not understand., type=server_error, param=null, code=null}}}

However, when I use Paths.get() instead, the request succeeds without issues.

Is this an expected behavior, or am I incorrectly using the SDK?

Start by reproducing the upload through FileCreateParams.file(InputStream) and compare it with the successful Paths.get() path in files().create. Trace how each input is represented in the multipart request, especially filename handling. Done means byte[] and InputStream uploads work without the reported 400 error while path-based uploads continue to work.