Installing PowerShell modules to the system (default) scope makes sense for modules that will be used by all users of the system. However, I prefer to not clutter the desktop of our users by dropping things in the All Users desktop. Likewise, I didn’t want to clutter the system modules of our users with modules that are really only used for system maintenance and support. Things that, frankly, don’t need to be even seen by the customers/users.

I thought it would be a non-issue. My processes run as the System user ( NT AUTHORITY\System ), and I could just Install-Module -Scope CurrentUser and it would be fine. I was wrong, see attached image.

The fix was to add a Documents folder in the System Profile. I've detailed this more on my blog:
https://blog.vertigion.com/2020/11/12/installing-powershell-modules-in-the-current-user-scope-of-the-system-user/