Yes, I believe the channels are bugged in the modded drivers, everything's working fine on generic drivers (same driver version).
EDIT: Just tested with a headset, I am experiencing the same thing, both head set and speakers are outputing sound.
Thanks for the update but it seems to mess up my channels/jacks. Eg: sound from real speakers would come out from my front speakers, I made sure I have the jacks inserted properly and everything went back to normal when I revert to an older driver, any idea why is this happening?