Default Bbm Voice and Zello microphone problem

Both apps have issues with microphone. Bbm voice and Zello's microphone functions over the receiver audio speaker(earpiece) instead of the phone's default located beneath. Did some test only to find that the problem exist in my Sony xperia z ultra. Tried other apps like Skype and phone calling did not appear to have the microphone problem and it worked accordingly from its default microphone (which is beneath the handset) Any thoughts on this? I am running 4.4.2 Build: 14.3.A.0.757.