Sure, here are some tips to help you fix smart playlist functionality problems:

1. Update Your Device: Ensure that your device is running the latest software version. An outdated system can cause many issues, including problems with smart playlists.

2. Check Your Settings: Make sure your smart playlist settings are correct. Any changes or errors in these settings can affect the functionality of your playlists.

3. Re-sync Your Device: If you're experiencing issues with your smart playlist on a device that syncs with a computer, try re-syncing it. This can often solve a variety of problems.

4. Rebuild Your Playlist: If a specific playlist is causing issues, try rebuilding it. Remove all songs, save the empty playlist, then add the songs back in.

5. Check Your Files: Make sure the files in your playlist are not corrupted or missing. This can cause your playlist to malfunction.

6. Reset Your Device: If none of the above steps work, you may want to consider resetting your device. This should be a last resort, as it will erase all data and settings.

Remember, it's always a good idea to back up your data before making any major changes to your device.