Default [Q] long press on bluetooth headest doesn't work

Hi
I have LG G2 korean version. This is F320K.
When I had stock rom and when I press and hold bt button on headset then will launch Qvoice.
With any other custom rom, I'tried around 5 after this action no reaction.
It looks like device doesn't recognize that commend.
When I start making a call I can stop calling or reject.
Anybody can help me? I think there is something removed from stock rom when custom rom is cooking. But I have no idea what.