This weekend I spent a bunch of timing liking individual songs from my playlists and saved albums so they'd all appear in the Liked Songs playlist.
I started by doing it via the mobile app but it was too slow, so I switched to doing it on my Chromebook. I went from about 150 songs to around 400 via my phone, and then from 400 to over 1000 via the Chromebook (spotify web version).
The "Liked Songs" playlist on my mobile device didn't update with all the songs I added on the Chromebook until I cleared all my cached and stored data.
Now using my MacBook Pro with the Spotify desktop app, NONE of those Liked Songs are reflected -- my playlist is still around 150 songs. I've tried logging out and back in, I've even uninstalled and reinstalled Spotify.