This bug seemed to start happening recently (around the May 11 patch).
When asuras pull their weapons out, their shield clips into the arm. This happens even with the smallest, thinnest shields in the game.
The bug fixes itself when the asura is in any sort of animation, like attacking with a sword. The animation makes the shield bounce out of the arm — it's pretty noticeable. But as long as the asura has their weapons out and isn't attacking, the shield will clip into the arm.
Obviously not the biggest bug in the world, but it does hurt some of the Fashion Wars vibe a bit.