I only see one "word" here, not two.
I get that the type of CAPTCHA has changed (why anyone would REDUCE the number of items to type in is beyond me, but whatever), but there may be some vision-impaired (or really dense) people out there who see that it says to type two "words," only see one, and then spend forever trying to find the other one. To clear up any confusion people might have, I suggest you tweak the wording of the login CAPTCHA instructions. All it should take is to go in, delete a few words, re-type one or two, and boom, you're done.