Commiting Mp3 Files to Folders in Gitlab through API

I am trying to commit a file to Gitlab through the API. The format of the file is .mp3.
The code had been working for over 6 months but now has stopped working, nothing in the code had changed. The file is commited to Gitlab, however the mp3 format has changed and I cannot play it anymore.

I have went through the Guzzle documentation and everything looks correct, and I have done the same for the Gitlab documentation about commits. I updated guzzle as well.

I am now using the laravel Illuminate/Http class to send the commits but the same thing is still happening. I am able to commit to Gitlab, but the mp3 file is not formatted correctly.

        $response = Http::withHeaders([
            'PRIVATE-TOKEN' => $gitlab_token,
            ])
            ->post('https://gitlab.com/api/v4/projects/.../repository/commits/', [
                    'branch' => 'test-branch',
                    'commit_message' => 'Updated audio file test.mp3',
                    'actions' => array(array(
                        'action' => 'update',
                        'file_path' => 'filePath/../.mp3',
                        'content' => base64_encode($var)
                    )
                ),
            ]);

If I do not encode the contents of the file to base 64 I get the error:

Malformed UTF-8 characters, possibly incorrectly encoded in file

Has anything changed on the API side that has effected how mp3 files are processed for committing? has anyone else found a solution (perhaps a Laravel or php helper function?). Thank you!

May be something changed in GitLab API?