Spotify creats Random Folders on my Mac

[AFX_1]

spotify works well on my mac
but creates a lot of folders in my folder /User/Music/ ("9f", "78", "ff",...)
Why are these created and how can I prevent it?
After uninstalling Spotify no new folders will be created. So it must be a problem with Spotify
When I delete the folders, new ones are simply generated again.