"The missing icon is also displayed for large files for which the thumbnail cannot be generated."

As my number of high quality photo's grow due to my phone camera I noticed more and more miniatures missing. This makes browsing though the catalog a real problem. trying to solve the problem I read: 

"The missing icon is also displayed for large files for which the thumbnail cannot be generated."

(https://helpx.adobe.com/elements-organizer/using/troubleshooting-catalog-issues.html)

These seems a rather strange and unwanted feature. Some questions I have:

1. Why not use a dedicated icon for this so users have a better understanding of what is the issue?

2. What can be done about it? As it is a growing problem.. 

3. How come some pictures have this missing icon and some don't as they were all shot with the same camera?

4. Why is the refreshed miniature not saved? When I refresh the minitaure it restores (so it actually is possible to create a miniature), but this miniature is not saved. Opening the Organiser agian will result in again displaying the Missing icon. 

I already tried emptying the media cache and restoring the catalogue. 

Furthermore, this seems to me an issue devellopers want to fix with prio 1. Because it's not fun not being able to see miniatures for some files and being told these pictures are missing!! 

I refuse to update untill to 2023 it's resolved.. so updating is not a solution for me. Actually this yearly paid expensive(!) update doesn't make me happy either.. but that's another post I guess..