I hope this helps

panda/src/audio/audio_sound.cxx

@@ -5,6 +5,7 @@
 
 #include "audio_sound.h"
 #include "config_audio.h"
+#include "audio_manager.h"
 
 TypeHandle AudioSound::_type_handle;
 
@@ -17,6 +18,7 @@ TypeHandle AudioSound::_type_handle;
 AudioSound::~AudioSound(void) {
   if (audio_cat->is_debug())
     audio_cat->debug() << "AudioSound destructor" << endl;
+  AudioManager::stop(this);
   (*_delstate)(_state);
 }