Basically I had an issue a lot of people have which preventes users from listening to some artists and shows a popup saying that the track is unavailable and to add it if you have it on your local files. I discovered it after trying to listen to Grimes and found some threads complainingabout the same. I foundthis onesaying they couldn't listen to Lana Del Rey, which I couldn't as well. Eventually asking some friends to test it and checking other threads with the same issue, I discovered it wasn't artist related because some people could play the artists that were "bugged out" while others couldn't.
I also found a ton of non-solutions like deleting local files, deleting other devices on the account, reinstalling and starting to play on a device then swapping to computer. None of it worked, while the web player always worked fine.
Eventually I found out (at least I think I did) that the problem was related to the new version. I don't have a link for IOS or Mac versions but I found these 2, for Android and PC.
Thanks for all your feedback, I'll make sure to pass this on to the relevant teams. You can always reach out by e-mail here, or on Facebook or Twitter on @SpotifyCares.
I recommend you to stay on the latest version available to make sure you're secure and can enjoy Spotify in the best way possible.
If you're having any issues with the latest version, be sure to create a new issue report, so it can get passed on for the tech team at Spotify to take a closer look. Let me know if you have any other questions.