Restore doesn't work for TV episodes

[KnifeFed]

After running the latest version on my TV library and none of the episodes got HDR/DV banners, only 4K banners (see #77), I tried restoring them. It only restored movie posters and then said it had been completed.

However, it wouldn't have worked anyway because I noticed that in each season folder there's only a single image, poster_bak.png, which is the poster for the first episode.

How do I reset all the episode posters now? I cleared Plex Media Server/Plug-in Support/Caches and refreshed all metadata but the posters didn't change.