DVR recording things I didn't ask for

Almost daily, when I go to recordings on my x1 box, it will shows that have recorded that I didn't set up to record. Often they are things I would never watch. We had a tech here for a different issue, and he said that maybe a neighbor's box was "talking" to ours and that we need a filter or some such thing. No one at Comcast seems to know what's going on. Do you?