I have mentioned before that there is acknowledged disparity between metadata within the EPG data and what is on thetvdb and other sources.
The problem was much more widespread when we were using TiVo data. With Gracenote it is a lot better but there are still cases of the EPG is different from other sources
It is for these reasons and to avoid having repeated recordings or loss of recordings, we stopped auto matching of recordings a long time ago and preserved the EPG data. At the same time, I made a recommendation that separate libraries are used for recordings to ensure this data is preserved and not does not get changed by scanning and auto matching. See Feb 2020 post EPG metadata is now retained for DVR recordings
