I have Plex set to scan my library automatically and run a partial scan when changes are detected.
In the last few days/weeks I have noticed when I add a file to the library, it takes a few minutes for Plex to recognize something has been added and to begin the scan compared to earlier when it would detect and scan almost immediately. However, if I add the file and manually scan the library, it almost instantly processes.
first question - how big is your library?
I’ve noticed mine started out fast and snappy when i added stuff, but after getting into a few thousand folders, it takes a minute or two. its no big deal its only a couple minutes, but sometimes it just gets STUCK. clicking manually scan stil only seems to do a partial scan, just tells it yes theres been a change.
sometimes it can take a while for the server to iterate thru your entire libraries folder structure to detect changes once it gets big enough. nothing to worry about.
TV/Movies all up probably just over 1TB, not that big, I’ve seen bigger. I did a test with a new library with 1 500mb tv file in it and it took like 5 minutes to detect the change.
I did speak to a few others on a different forum and they confirmed the same issue these days when a while back it would instantly detect and process.