Audio disappear while compressor from HD to SD

Got the mov file which is ProRes 422 from company. It has audio When I use compressor from HD to SD setting. Use pro-res setting with 720x480 and pixel aspect as ntsc ccrir 601/dv (16:9) and audio set as pass-through. When it is done, audio just disappear. I wonder why. I did same thing with other two and they do have audio. How come? I Use Compre