If you have a folder that has a special character (like “, ”, á, etc.), when trying to display a playlist located inside the folder, you will get “Empty.”
The special characters do display and work OK for file names and playlist file names.
I used the latest firmware (01.01.20) and an external microSD card.
To duplicate the bug, create a folder named something like Guantánamo on an external microSD card. Inside the folder, place some mp3 files and a playlist for them. Insert the card into the Clip Zip, let it refresh, go to “Music,” then “Playlists.” The playlist will be there, but it will be empty after selecting it. If you rename the folder to say Guantanamo, now the playlist will work (even if the playlist is named Guantánamo, with the special character).