Playlist images no longer being generated

[user-removed]

I'm having an issue where the cover images for certain playlists are no longer generating based on the first four tracks of the playlist. I thought I would try uploading my own cover images for a few playlists, so I tried that, but I ended up preferring the auto-generated cover images, so I removed my uploaded images. The problem is, for each of these playlists I tried this on, the auto-generated cover image doesn't reappear. Has anyone else experienced this bug? The art doesn't show up regardless of how I view my profile (desktop app, iPhone app, web player, signed in, signed out). It makes my profile look far less attractive, and I'd really like a solution to this.