New/Some music appearing in ? folder

Is anyone else seeing the issue I’ve been experiencing for a month or two?
Add new music to my Volumio connected USB drive.
Go to Music Library, USB - Click on 3 dots, Update Folder

Wait a while, go to Arists view, see the weird white with red question mark folder containing some artists and albums, not necescarily the one/s I just added and updated.

The only way to make the ? folder go away is to restart Volumio.
The same thing happens with my second Volumio which connects to the first as a NAS for it’s music library.

After adding a new album (Radiohead - In Rainbows)

After doing the Update folder on USB, MUSIC

Contents of the ? folder (unrelated to new music just added)

This seems to be 100% repeatable.

R Pi 3B+ USB drive attached to USB port
Volumio version 3.866 Oct 2025