issue: unsaving song from lockscreen doesn't work

[user-removed]

Device:

 Oneplus Two

Operating System Version:

 Android 5.1.1 / OxygenOS 2.2.0

Spotify Version:

 4.7.0.878

Description:

 When in lockscreen you can save and unsave songs. Saving songs works ('+' changes into a tick 'v') but unsaving a song (tick 'v' changing back to a '+') doesn't work. For that I have to unlock my phone and unsave the song trough the app (that does work). See screenshot (red circle).

To reproduce:

1. Play spotify song (doens't matter if it's already a saved song)
2. Lock your screen
3. Save the song by clicking '+' if it's not already saved
4. Try to unsave the song (-> doesn't work)

Workaround:

 Unlock screen and unsave it trough the app.

Additional information:

 N/A