What you see: Ugly black borders around the top, left, and bottom of the tiles (even extending beyond the rounded corners), and to the left of the "More" buttons.
What you should see: Understatated grey borders, like the one around the list of categories.
software-center 5.1.13.1, software-center trunk r2906, Ubuntu 12.04 beta 1
1. Launch USC.
2. Scroll down to the tile views.
What you see: Ugly black borders around the top, left, and bottom of the tiles (even extending beyond the rounded corners), and to the left of the "More" buttons.
What you should see: Understatated grey borders, like the one around the list of categories.