We've received reports that the Crossfade feature isn't working correctly on the desktop app. No matter how many seconds are being added, it won't work and after returning to the settings page, it's set to a random amount of seconds.
Thanks for your patience while we looked into this issue.
We’re happy to inform you that this should now be fixed! Just make sure your app is updated to the latest version.
If you still don't see the change, try the following:
Open Spotify, turn the Crossfade off and then restart Spotify.
Turn the Crossfader back on and change the value.
If you're still having trouble, make sure to post a new thread in the relevant help board here.