If the guide data is missing only on your ATV but NOT the web UI guide, that is a different issue.
If the guide data is missing on both your ATV and the web UI guide, the below applies.
Could be an issue with the Pluto for Channels docker getting the EPG from Pluto which will appear in the Pluto for Channels docker container log as
mv: can't rename '*playlist.m3u': No such file or directory
mv: can't rename '*epg.xml': No such file or directory
Could also be the timing of when the Pluto for Channels docker container grabs the EPG from Pluto and when Channels DVR refreshes it from the container. I modified my Pluto for Channels docker container to grab EPG from Pluto every hour (normal is about every three hours) and also use a task to update the playlist.m3u and epg.xml in Channels DVR every hour after the Pluto for Channels docker container grabs the Pluto EPG.
That way my 12 hours of Pluto EPG is never more than 1 hour old.