Plex prevents computer from entering the sleep state while streaming, but when the content ends, computer goes straight to sleep mode if the idle countdown is shorter than the content’s duration. This is spatially bad for series episodes, that are shorter, requiring you to wake the PC up between each episode (if your sleep timer is 30min, lets say).
My suggestion (if that is possible): Plex should hold the PC’s sleep timer for the content’s duration, releasing it to start counting down after the movie/chapter have ended. This way the server will never be down between movies or any content switch.
Hope this is useful for more people. Thank you! : )