This is not necessarily a Windows version of Kodi issue (as It occures on both my Nuc and Nvidia Shield TV), and I have seen this issue before.
Several years ago (I believe Kodi 14), I noticed an issue with some movies not showing up in my database (even though they were scrapped correctly using MediaElch, and had perfectly good .NFO files. In the original case, the movies had the title Ghost in them…
Ghost (1990) – Bluray\Ghost (1990) – Bluray.mkv
Ghostbusters (1984) – Bluray\Ghostbusters (1984) – Bluray.mkv
Ghostbusters 2 (1989) – BluRay\Ghostbusters 2 (1989) – BluRay.mkv
What happened was, that only the first movie (Ghost) was displayed in the Movie database, and the others weren’t able to be seen by the database (no amount of adding, removing, or updating the database would fix the issue. So I posted the issue here, and it was eventually fixed in Kodi.
Fast forward to Kodi 17.1. Same issue, but new movies.
Suicide Kings (1997) – BluRay\Suicide Kings (1997) – BluRay.mkv
Suicide Squad (2016) – BluRay\Suicide Squad (2016) – BluRay.mkv
Could not find Suicide Squad listing in Kodi. I am using the Aeon MQ7 skin, so I switched to Estuary Skin, but that made no difference. Removed the movies source, and re-added it, etc. The movie would not show up.
So a temporary fix, was to rename the folder to DC’s Suicide Squad (2016) – BluRay, and then Kodi was able to find and add the movie to the database.
Still there appears to be an issue, and I wanted to let the Devs (and everyone else), know about it (for a possible future fix), and how to fix it currently.