I installed X86/X64-Version on a SD-Card and ran it on my PC. Same thing: “My Playlists” does not work.
BUT: When I used my girlfriends Spotify account as login for the Spotify Plugin, “My Playlists” works fine!!
So it has something to do with my account! Is there any limitation (number of playlists, etc)?
The fact is that if you go back to version 2.114 it works fine. That is, it is not your account itself.
In my case I am not sure about that.
Right now “My Playlists” works alright on my system with 2.118!!!
After I found out yesterday that with another Spotify account than mine everything was fine, I deleted some of my playlists. Than I configured back to my account (and went to bed 
). And today - what a miracle - I can reach My Playlists from my account.
I have no idea what really solved my problem for now: Temporarily using another account, deleting some playlists or today’s moon phase. I’ll see how stable it is the next days…
Jaja, the moon phase, sure!