Why are the Desktop, Documents, and Downloads folders empty in Samba shares?

I'm sharing between iMacs with Samba. Both computers are running macOS Catalina (10.15.3). To get full disk sharing to work, I opened Settings > Security & Privacy > Privacy > Full Disk Access and added smbd.

I can mount a Samba share from one iMac on the other and see the full drive. Everything seems to be working except for this very strange behavior: the Desktop, Documents, and Downloads folders (inside my user folder) all show zero bytes, zero items, and appear empty when opened.

None of those folders are actually empty. I can login with VNC and see the items in them fine. The permissions appear fine (my user has read/write access). All the other folders (inside and outside my user folder) show their normal contents.

What is causing these specific folders to appear empty and how can I fix it?

I double-checked the permissions (they were fine) and then restarted both client and server, and now everything is behaving normally. So maybe it just needed a restart?