Missing Files in Explorer

I’m using the desktop client 3.4.1, when someone else uploads files, sometimes (no regularity) they don’t show in my Win Explorer, but when I right click on the folder “show in browser” the files are there. Some problem when I upload, and the other user tries to see them.
Any tips?

I’m hitting a similar issue.

Shared folder → Folder is visible in win explorer, but not the files. But in browser the file are there.

. . .

Thanks for any idea