Default [Q] notification problem please help

hey im running on touchwiz 4.2.2 rom on my i9505

when i hav my stock samsung headphones plugged in i don't get notification sound when i am listening to music on spotify. the music just stops and it is silent and no notification sound. and when i unplug them it is all fine. does anyone here know why this problem is occurring ?

i have just made a clean firmware flash so it is from a clean flash!!