Syncing audiobooks removed iCloud Music Library playlists

I manually synced some audiobooks to my iPhone's Books (through Finder, not the Music app). Then, despite the fact that my iPhone uses iCloud Music Library, all the playlists in Music disappeared on the iPhone. The playlists are all still present when I open Music on any other device, including the MacBook I used to sync the audiobooks. The sync shouldn't have touched Music at all, since iCloud Music Library is on for all my devices. What happened? How do I get my playlists to appear on my iPhone again?

iPhone SE, iOS 18.6.2, iCloud Music Library sync is ON

2020 MacBook Pro, macOS Sonoma 14.4, iCloud Music Library sync is ON