You’ve uploaded files to your iCloud Drive on another system, but an hour or more later other systems can’t see them. Here’s a solution.
When you upload a file to iCloud Drive, the steps involved are complex. They’re outlined and diagrammed here, with pointers to how to diagnose and resolve problems.
A new app to help you work out why those files aren’t uploading to iCloud Drive, and more. Performs a test upload which could even fix a problem.