Exclamation HD youtube video and Bluetooth

Dear all,
I have a weird issue with my LG G2 D820 with stock Kitkat.
If I watch an HD youtube video via wifi only it loads and plays smoothly, however if I turn on bluetooth (to use my speaker system) the video will not load as fast as while in wifi only and therefore I cannot play it in realtime.

It is like the Lg G2 try to load the video using wifi+bluetooth or I don't know...

Can someone please check and see if he has the same issue as me? Is there any workaround?

Thanks in advance