Samsung Galaxy S9
On my phone, certain local files become greyed out after some time of them being on there. I can still play these files they just won't play when I play all songs on a playlist. They still play on my computer just fine in a playlist just not on my phone. one solution I've found is to clear my data on my mobile Spotify app and then redownload the songs however it is only a temporary fix and I hope to find a more permanent one.