Offline songs disappears (without being deleted) after a system update

[bachisuto]

Hello,

After a system update (even a small one) the Spotify app doesn't show my offline songs as downloaded. However, the songs aren't deleted because the Spotify app still takes several gigabytes on my internal storage.

This problem appeared on both Nougat and Oreo on my Oneplus 5T and on Nougat on my Galaxy A5 (2017).

Is it a known issue?

Best regards.