Do you think the JUC would also damage the clash when they are stacked together or it only happens to the love? thx
It won't damage the Clash due to the design.

Hairline scratches that you can't even see? Maybe... but because the Clash has so much movement and isn't a "solid" piece, and in addition the shape of the "spikes" of the bracelet and the small amount of actual surface area touching the JUC, you'll be fine.