I've seen this on Scientific-Atlanta DVRs too -- the 8300 and similar models used by cable companies.
I think the problem is they only look at a show's Title to determine is it's a new or repeated showing. There's more information available to determine this, and Tivo and ReplayTV use it wisely -- but not the simplistic recorders from the DBS and cable companies. I think they literally don't understand how TV stations operate...
The typical show schedule has a variety of data that could be used:
Flags for new/rerun, CC, letterbox, color/bw, HD, and others.
But, does a particular OPG have all of this info, and even if it does, does a particular recorder use all of this info?
I see the problem frequently when there's a multi-part series. Every showing has the same Show name, but where it blows up is if every Episode has the same name too, differing only in the description.
For example, the PBS series "American Experience" (Show/Series name) might have a two-part presentation called "The Cowboys" (Episode name). The first part might have description "How Cowboys got started" and the second "Cowboys of the future", but to the brain-dead recorder, it's simply two showings of the same Show+Episode, therefore only one gets recorded.
Along with DirecTV's recorder, my SA8300HD won't record seeminly identical episodes, but my ReplayTV will. I learned this long ago and now when using the SA recorder I must locate the future episodes and mark them to record -- if I can, made difficult because the recorder only gives me the next 6 days of schedule. I can't even set it to record a show one week from today, unless I wait until tomorrow. But that might not work because it routinely skips the schedule of one random day a week and never downloads it. And of course there's no way to record by searching for anything. What a joke! So, I also set the same show to record on the ReplayTV, knowing I'll get it for sure and will just a have lesser quality picture rather than nothing.
However, the reverse problem can hit Tivo and ReplayTV units. While the proper listing format is to use the same Show name every time, and vary only the Episode name, if the TV station instead messes with the Show name, ANY recorder gets confused. The "record all episodes" mode doesn't work because they don't see the episodes as of the same show. Example: My wife liked Hallmark Channel's McBride series of movies and asked me to record them. But instead of each one being Show: McBride, Episode: Whatever, Hallmark changed the Show name each time. Now they were being brain-dead, not considering that this practice made recording very difficult. I had to use ReplayTV's ability to search for a keyword within a title or description -- but at least I had that tool. There was no way to record series on my SA8300 because it can only do an exact match on Show name but Hallmark gave each a one-of name.