Why is KODI not showing the correct video file names?

I have a Raspberry Pi running KODI on top of OSMC. It is a pretty recent release because it usually auto-updates on restart.

There is a 1TB USB disk connected to the Pi which holds all of the MP4 video files in a suitable directory structure.
To play them I navigate through the menus via FILES and into the MEDIADRIVE disk to select the file I want to show.

This worked just fine until a couple of weeks ago when the file selection display started to show totally false titles for the files.

I have for example 3 recordings of SVT transmissions taken 3 different years all from the holiday music performance on Dec 13 of a Lucia concert.
These files have names LUCIA_2013-12-13.mp4, LUCIA_2014-12-13.mp4, LUCIA_2015-12-13.mp4.
Now when I navigate to this folder on the MEDIADRIVE (the USB disk) there is no display of these file names at all!
Instead what is shown is only LUCIA for the first one, then two totally different names.
And the LUCIA title when selected shows some extraneous information of a science fiction film including non-related graphics!!!!!

It makes no sense at all to me and I would really very much have my file view back where the file names define what content there is.

What could have happened and how can I clear this rubbish out?
I do not believe it is a Raspberry Pi “feature” but rather a bug in KODI so that is why I post here.