I uploaded a small PDF to my Proton Drive account on iPhone. Several minutes have passed, and Proton Drive for macOS continues to act as if the file doesn't exist. The menulet icon shows a check mark. The dropdown menu shows "Synced 5 minutes ago". But the Proton Drive folder doesn't have an entry, even an uncached entry, in Finder.

Went to the Proton Drive Web app. Both it and the iOS app show the PDF. But the desktop app fails to witness it.

I tried pausing and resuming.

I tried relaunching Proton Drive.

I tried updating Proton Drive.

Same problem.