That's not a bug dude. Read carefully why the lines are added in build.propsame here in Xperia SL lt26ii stock 6.1.2.A.45 room
Another bug: i can't enable clear phase and some audio effect in Sound Enchangement -> More. Build.prop edited. Don't know why.
Those lines are to turn on the audio effects, toggles in sound enhancement are not working yet.