null exception error at releasing FMOD

Unity Engine
1

My version of unity editor is 2.6.1 pro license.
it randomly happens on various PCs when calling release function.
App calls this release function at OnDisable().

  public void release()
    {
        //cleanup routine here
                
        //Shut down
        FMOD.RESULT     result;
        
        if (fmod_sounds != null)
        {
            for (int i=0; i<fmod_sounds.Length; i++)
            {
                if (fmod_sounds[i] != null)
                {
                    result = fmod_sounds[i].release();
                    fmod_sounds[i] = null;
                    ERRCHECK(result);
                }
            }
        }
        

        if (system != null)
        {
            try
            {
                result = system.close();
                ERRCHECK(result);
                result = system.release();
                system = null;
                ERRCHECK(result);
                Debug.Log("FMOD release! " + result );
            }
            catch (Exception ex)
            {
                Util.Exception_Log(ex);
            }
        }
    }

this is error log

does anybody has any idea of solution?
thank you.

2

since Unity 2.6.1, unity uses FMOD internally so if you use an fmod addon you might messup the state of the engine and cause a crash I guess