Some downloaded tracks become inactive / unusable on Apple Musicplaylist

I create playlist and download them to a sim-less device (i.e. only connects to WiFi) and use this to play them back.

On a couple of occasions, selected tracks have become unusable; they remain in the playlist but the downloaded icon is no-longer present, hence they are skipped straight over without any warning. This happened a few months ago with a couple of Fatboy Slim tracks, and today with Blood Red by Feed Me.

I used the playlist twice yesterday without issue, then today the song is skipped.

When I connected to WiFi, the song still wouldn't play from the playlist, pressing the screen did nothing despite the title appearing on the playlist. I then searched, found the same song, and was able to add this back to the play lists, but the old version still appears.

I have a video I can link to if I can figure out how to post it, but below is a picture of the playlist as it appears with the track seemingly there, but frustratingly not! I'd really appreciate any help with this as it's problematic to find out that a track won't play only once it hasn't played!