Some songs from a downloaded playlist are greyed out when I'm offline

[darkcompanion]

Hi, I have several playlists that I've downloaded to play when I don't have internet access.  

However, on some of the mixes, a portion of the songs are greyed out when I'm offline.  
But when I'm online, those songs are suddenly available and no longer greyed out.  

It seems to be related to particular albums.  
For example, one artist that I like has two albums.  
I have multiple tracks from both albums on playlists
and only songs from their second album remain playable when offline

while the songs from their first are all greyed out when offline.  
As soon as I connect to online mode I can listen to both albums.  

This isn't limited to just one artist though.

I went as far as to make a playlist based solely on the first album, and downloaded it, and while it allows me to do so and the downward facing arrow in a circle appears green, the playlist is not available offline, making the point in downloading it pointless.

I also "un"downloaded some playlists, thinking maybe there is a limit to the number of songs you can download and that was the reason.  But freeing up space by doing this did not make a difference and the songs still would not download for offline playing.