Why doesn the audio work in both earpieces (Right/Left) while on an active call?
Both earpieces (Right/Left) are used when the Bluetooth Advanced Audio Distribution Profile (A2DP) is activated when listening to music or watching a video. When you make a call on your Nokia device while using a Bluetooth headset, the Hands-Free (HFP) or Headset (HSP) profile would be activated. Only the Right earpiece is used at this time. This is a Nokia safety feature as the headset may be used in a vehicle as a Hands-Free device. This allows the user to still hear the environment around them while on an active call.