Weird Sound Problem. Youtube=Sound, No Youtube=No Sound

OK So I have a weird problem that I have no idea how to fix. I’ve done the normal stuff, uninstall reinstall drivers, repair game, switch audio device, remove all audio devices and add them back one by one.
The problem is this, and for extra fun it’s intermittent. I play wow on one screen, and watch/listen to youtube on my second screen. Sometimes, when a youtube video ends, Sound in WoW is disabled. I can be mid fight and bam! Silence, no DBM, no I need a target, no dramatic music. This continues until I either start another video OR go into setting>sound and switch audio device back and forth from the device I am using to default and or other devices until wow is suddenly happy and starts making noise again.
Anybody got a clue as to how to resolve this?