I don't know if it's a coincidence or not, but since the beta started I have had a large number of times where a fill-in-the-blank question was converted to multiple choice, and one of the "incorrect" answer choices was actually a synonym for the correct answer. Sometimes, it's even a word I tried before the question changed answer type. Heck, sometimes the site tells me to pick a different word, and then the word I just tried shows up again when the answer choices refresh. I've pretty much never seen this happen before; previously, the only issues I saw with the incorrect answer choices were with terms the site didn't recognize as synonyms, or edge cases like with homophones or homographs.
I think it was coincidence. I took a look around, and I believe the issues are coming from the bump in priority that the misspelling engine got sometime this year. I have added additional checks to help it determine whether or not misspellings might indeed by correct, alternate answers. Let me know if you see any more (through the in-quiz reports). Thanks!