My Blues playlist was wiped out after moving to a new iPhone

I've been collecting blues songs for years into a playlist I named 'Blues'. Today I played the playlist on my phone and it ran out after 8 songs. It used to have more than 500 songs in it.

I turned on syncing when I got the phone a week ago. And I can see on my Mac that the playlist is shrunk to 8 songs (likely ones I added since I got the new phone).

I'm wondering if something special happened because of the name of the playlist being an actual genre. All of my other playlists look fine.

How can I get my playlist back?

I have an Apple Music subscription and I still pay for iTunes Match that I got years ago when that was originally offered.