It may not really be a Spanish language track. Not all of the information provided in the guide data is accurate and not all of the content is properly assigned. I've tried a couple of SAP audio selections just to see if it worked and both were mislabeled. They were clearly different than the standard audio track as the quality of the sound was different but they were both just lower quality versions of the English audio track. (I assume analog rather than the default digital.)
Try the other audio tracks if any are available. Maybe the Spanish is on one of those.
Try the other audio tracks if any are available. Maybe the Spanish is on one of those.