Apple Music gained animated playlist artwork with the release of iOS 14, but it looks like Apple is now extending the feature to select album covers in iOS 14.3, too.
Animated album art in Apple Music has been spotted by a Redditor on albums including “12 Questions” by Future Utopia, “Detroit 2” by Big Sean, and Pearl Jam’s “Gigaton.”
Source: Apple Music to Get Animated Album Artwork in iOS 14.3 and macOS 11.1 – MacRumors