No idea how long this bug already exists but when you open a library panel for a game that is divided into many 4 GB files then most of these files are not being displayed.

As an example I included a screenshot for the game Middle-earth™: Shadow of War™. You can see that after Part 8 the panel will be cut off making it not possible to download the Parts 9–30. Only reloading the whole library page and then opening the game panel again will display all available files correctly.

I think this has something to do with the offline files being collapsed when you open a panel for the first time. Once those are folded out and you reload the library and panel everything works.

This has been a thing for years

Huh. Once you open the panel, it stays open forever for all games (unless you sign in on a different computer or something, probably) so I had no idea that was a thing. Anyway you can always use Galaxy to download offline Windows installers without having to deal with a zillion parts.

It is very good quality spit and Duct tape, mind...