Looking at that one-pager linked at the bottom[0], it seems there's only 12 error messages in Spotify where this gets applied.
While I have certainly seen at least five of those, I'm not surprised that you've managed to trigger the one without it in two minutes. After all, an app like Spotify probably has significantly more than 12 error messages in it.
Of course, Decided to see how fast I could trigger an obscure error message in the app. 2 minutes in:
1. Enable offline mode 2. Click a song that hasn't been downloaded yet 3. "Song unavailable" is the error. No explanation why.