Songs keep disappearing from my playlists

[804R]

Hello

I'm having some serious issues with songs disappearing from my playlists, the one labeled "Songs" in particular. Now let me get this straight: the songs are not being deleted from Spotify, at least not as far as I'm aware. The latest was the song "Runaway" by AURORA that was there this morning and gone now. When I go to the artist's page, the song is still there and I can re-add it without any issues. 

I've experienced this several times before, but this is the first concrete one I can report. 

This needs to be fixed. I can't keep track of thousands of songs and losing one without noticing is a serious bummer. 

This happens across all devices (Windows 7, 8.1 and Android). 

Best regards

804R