I know I've seen this same error in the forums somwhere, but I can't seem to find the post.
I've gone through Challenge 15 (Don't Blink) a few times and entered the correct answer. It says each time that I entered the correct answer (Congratulations/Redirecting), but then refreshes and shows me the puzzle again. After going to the home page, it doesn't show that I've completed it and doesn't up my rank.
Thanks,
scarabaeus