For most of my ads, I have specified rounded corners in the ad layout area, under "Corner Style", and up until a few weeks ago, my ads have always had rounded corners. Now the corners are all square, 90 degree angles, even though my layout shows that I have chosen the middle corner style, slightly rounded. This isn't browser specific. Even in the layout page, no matter what I change the corner style to, the ad corners remain squared. (see attachment).
Could be just a temporary glitch. Could you provide a link to your site, so that I could check it out in different browsers to see which ones are failing do show rounded corners?