I’m also using plex via library and with infuse 8 I have a similar issue that was not presented on 7.
Whenever I call plex to update (for new movies, episodes etc) infuse 8 is not reflecting the changes on my atv 4k. To update now I have to manually enter on some content details, go back and then infuse reflect the changes, while on infuse 7 the plex changes were reflected immediately so please fix it.