Board Thread:General Discussion/@comment-220.255.1.87-20130525055713/@comment-3153244-20130529063453

Yeah, on my test account, I got:
 * 1-1: 50%
 * 1-2: 45%
 * 1-3: 31%

and I earned the achievement. I'm guessing this new bug came in along with update 1-3.