In binaural mode, one of the stereo voices is noticeably quiet on the left channel

There’s a drop in volume with one of the 6 stereo voices on the left side. Only noticeable in poly 1 & 2 modes with binaural activated. tried a factory reset and voice tuning calibration with no luck of a fix. out of warranty - Am I sol and in need of repair or is there’s something i can do from home to fix?