I’m getting this sound bug too… It’s so annoying, I only get this when I’m in WvW.
At first I thought that it was something wrong with my PC. But then when GW2 crashed after a while it stopped so I figured it came from the GW2 client. I hope that they fix this pretty soon. I can’t even play 30min of WvW and now I need to reqeue for WvW… awesome…