Plex should analyze the movies/shows during the maintenance window if it has enough time. As a test, set Scheduled Tasks to run from 0000 to 2300, then stop & start Plex Media Server. The scheduled tasks should start shortly after PMS starts.
For manual analysis, analyze the season or episode, not the show or entire library. Or perform the Plex Dance as @Divideby0 mentions.
From the Plex docs
- Manual Intro Detection: You can force detection for a season or an episode by using the Analyze action in the options menu for them
- Manual Credit Detection: To do so, simply use the Analyze action from the options menu of an episode or a movie in the web app..
Yeah, I forgot to link in the support document: Investigate Media Information and Formats.
