Each single cover artwork in the music app is cropped left and right in Sequoia 15.0 (24A335)

On my MacBook Pro (M1 Pro, 16GB, Sequoia 15.0 (24A335)) each single cover artwork is cropped left and right in the music app, although the provided jpegs are perfect squares of 600x600 pixels.

The red borders left and right should be as thick as at the bottom, but they are not. This is the same with every other of my 1400 cover arts.

When synchronized they look perfect on iPhone, iPad and appleTV.

Does anyone have this problem too? Is this still a bug in Sequoia or do I make a mistake or ...?