ma_sound_is_playing() sometimes returns true despite sound finishing

[strager]

I registered a ma_sound end callback with ma_sound_set_end_callback(). The callback notifies another thread, and that thread queries ma_sound_is_playing() and ma_sound_at_end() for the sound.

I observe that sometimes ma_sound_is_playing() is true. (ma_sound_at_end() is consistently false.) This is unexpected; I consider this to be a bug because I expect ma_sound_is_playing() to always return false inside the end callback.

I tested on Git commit 4a5b74b (version 0.11.21).