Thanks for the responses and help guys.
I was only a couple days into running Plex when I had some issue or other, and found the hint to move the Local Media Assets to the bottom and refreshing the metadata. I did that for both Movies and TV Shows, and that definitely fixed whatever was bothering me then.
With regarding to the file names, aside from being a personal preference, as I said above they are a necessity for many things. For instance the Zappiti boxes that friends who connect to my servers use (and I had planned to buy before deciding to go with Plex instead), require the scene names for the files in order to properly find the metadata and subtitles and whatnot. Renaming all the files to delete the (quite important to me but obviously not to you) information is simply not an option.
@pshanew and @JuiceWSA:
The file is already in a folder called Extra Ordinary (2019)
Interesting and good to know that Plex ignores anything in brackets.
I have indeed become very familiar with The Plex Dance in the past week or so, trying to get this movie to show up 
Just did it again now, to start clean before testing.
Here’s what I’ve now tested:
- Created two copies (in a different folder) of the file, one named Title (Year), and another where I kept the scene name with all dots, but put everything after the year in brackets.
- As the last step of The Plex Dance, I moved the Extra Ordinary (2019) folder with the normal scene named file into it’s correct place, and did a rescan. Watching Plex run, it actually adds the movie to the movies list for a second, but then the movie disappears again, nowhere to be found again.
- Moved the Title (Year) file into the Extra Ordinary (2019) folder, which now two identical files with different names and did a rescan. Nothing happens. Did another rescan, and now the movie pops into Plex, with a duplicate. Both named files files show up just fine in that list.
- Moved the Title (Year) file back out of the folder, and did a rescan. The duplicate vanished, leaving the scene named file active and visible in Plex. Did another rescan, and then the movie disappeared completely.
- Moved the scene file with brackets into the folder, and did a couple of rescans, which brought in the new duplicates, just like it did for the Title (Year) named file.
- Moved the bracketed file away, and again one rescan removes the duplicate and leaves the scene named file visible, whereas a second rescan removes the movie entirely.
- Emptied the Extra Ordinary (2019) folder and rescanned a couple of times.
- Chose a random movie from my collection, made a copy of it, and renamed it to the Extra Ordinary scene filename, then moved that brand new and completely different file to the Extra Ordinary (2019) folder.
- Did a couple of rescans, and wonder of wonders, the movie is added to Plex without problems.
IOW, there’s something wrong with the actual file, that causes Plex to not be able to understand the scene filename. That exact filename works just fine on a different file.
- Just as a joke, I created an empty txt file, and renamed it to the scene filename with mp4 filetype. A magic 0kb movie was made. A couple of rescans did nothing, obviously, but it was a fun experiment
- Joke 2.0: Renamed the empty txt-becomes-mp4 file to Title (Year).mp4 and moved the original scene named file into the folder again, just to see if the combo did something. Obviously that failed as well.
So to solve this particular issue, I’ll just keep the brackets on this movie, thanks Juice. I just hope the brackets don’t mess with Zappiti’s functions.
But it’s too bad that I can’t 100% count on Plex to actually see all movies at all times.
@JasonNalley Oooh, thanks for showing me that there is a quote function. I was looking for it but didn’t see it before. The more you learn! 
I honestly thought I was answering you perfectly well here.
As for Plex being “a fickle beast, especially when it comes to naming and embedded tags”, I obviously didn’t know that before tonight. I’ve only been using it for a couple of weeks.
Perhaps if you’d opened with that nugget of wisdom when I first said that the name can’t make a difference because the movies are all named the same way, then we could all have gotten off to a better start and I wouldn’t be awake at 4am composing walls of text that annoy you. 
