I received an email from Spotify (entirely in Chinese). Ignored it.
Turns out that it was telling me that I have to change my password.
But no English translation!!
This is what it says (courtesy of Google translate):
Please update your Spotify account password
Hello Spotify the User:
To protect your Spotify account, we have reset your password. This is because you use the same password for other services data leakage accident occurred, so we think your Spotify have hacked possible.
do not worry! It is only a preventive measure Yet no one else entered your Spotify account, your data is still safe.
To create a new password to be able to continue to sign in the future Spotify, please just press the green button on the big side.