I get the soution: Search a song / play it / select the song that is playing and select playñist while it is playing / playñist will apear, maybe show an "loading..." just wait and all playlist will apear.
Got the playlists back in an LG smart TV with the following: 1. Uninstalled Spotify 2. Turned off and unplugged TV for 10 secs 3. Turned on, installed Spotify 4. For unknown reason, still autologs in with my account but the playlists aren't there 5. Went to settings, moved selection to my account with the intention of removing account connection 6. Pushed OK and it immediately prompted me to log in again (Didn't have the chance to actually select "remove account", prompt to log in followed right after selecting my account). 7. Used Facebook account to log in RESULTS - Playlists appeared, don't ask how or why - LG TV still doesn't appear in the list of devices so can't control it with my PC or mobile app
I had no playlists on my LG WebOS TV for weeks dating back to January 2017, even gave up trying contacting support after a useless conversation on Twitter. However, I just logged in to test it out and playlists are appearing again and work properly. Not sure if an update was released, but logout/login and give it another shot if you're still having trouble.