OS: macOS 15.5
Processor: Apple M4 Pro (arm64)

// change
Music music = LoadMusicStream("resources/country.mp3");

// to
Music music = LoadMusicStream("resources/sound.wav"); // just so we don't have to wait as long
music.looping = false;

if (framesLeft <= subBufferSizeInFrames)
{
    if (!music.looping)   /*== this is being executed too early ==*/
    {
        ma_mutex_unlock(&AUDIO.System.lock);
        // Streaming is ending, we filled latest frames from input
        StopMusicStream(music);
        return;
    }
}