It doesn't scroll vertically anymore; long lyrics just get clipped off the bottom. This is broken in master, but fine on the stable branch. Git bisect says the problem was introduced in https://cgit.kde.org/elisa.git/commit/?id=efe69043538e58cf5025b2a6f60416f9842e9474, which I can confirm. Looking at the diff, I can't understand how this could have regressed the Now Playing view.
This turned out to have been caused by a qqc2-desktop-style regression that was just fixed in https://cgit.kde.org/qqc2-desktop-style.git/commit/?id=6995b4ae81a2f3ca3c24d2fa6d1560bfe0898737