Not so long ago there was a bug where players would lose sound effects, but incidental music would keep playing. If they entirely logged out and logged back in it corrected the issue. Over the last 2 days I have had this happen again to me in PvE dungeons and sPvP. If I try logging out, my entire computer freezes temporarily and gw2 can’t be exited via task manager and an entire restarted is needed.