My MP3s are now greyed out in my Apple Music playlist

I have had a certain playlist on my Apple Music app that contains some purchased songs and some MP3s that I have had for many years (originally ripped from my CD collection). Now, the old MP3s are greyed out. The songs I purchased (both from Apple & Amazon) are not. I can play any one of the old MP3s by selecting it in my library individually, but it will be skipped in the playlist. Is this due to some "online purchased only" policy in Apple music?