If you are running into an issue where you do not get audio through both channels of the headphones or you get intermittent audio that may cut in and out as you move your head, please ensure that you are connecting the headphone cable properly.
For the iOS and Android cables, the connector with two rings plugs into the headphones. For the longer 3 meter cable, the smaller, non-threaded connector without the OPPO logo plugs into the headphones.
When connecting the cable to the headphones, ensure that you are pushing hard enough to hear the cable click into place. If the cable is not fully seated, you may experience no audio or intermittent audio through one or both of the channels.