U-VERSE RECORDS SAME SHOW ON HD AND NON-HD CHANNELS

My wife records several series. I didn't set up the series recordings so I don't know what she did wrong (?), but: when a show that's set up to record the entire series begins to record, it records on both the HD channel (intended) and the non-HD channel (not intended). Of course, this doubles the bandwith used. I kill the non-HD recording, but if I "cancel series" on the non-HD channel, it cancels both. I haven't figured out how the double recording happens, but it never happens on series recordings that I set up. Anyone know about this? Thanks-B1gMike in MO.