My appleTV doesn't appear to be pulling the new guild data as the server downloads it. If I launch channels on my apple TV I get guide data for about a week. (not sure the default amount). Then a week later I have no more guide data. I have to force close channels on apple tv and when I launch again, all the guide data is updated. I think I have had to do this now for the last 3 weeks. It's obviously not the DVR server but the apple TV app not pulling the data from the server.
If you check on your server, for an HDHR or TVE source that uses gracenote guide data, it grabs 16 days of EPG every morning. Other sources will vary in duration, like Pluto which is 12 hours.
There are quite a few posts where users state they have to force close the app to get it to update things, including guide data.