Is something up with the word-familiarity ratings?
For the past couple days, Duolingo has been telling me that I have mastered every word I encounter. In that little sidebar on the right at the end of a lesson, where it shows you the words that were covered and how familiar you are with them, I've been getting four bars out of four for every word, including words that were just introduced that lesson. Are other people seeing this? I do the "practice weakest words" drill a lot, but I think it would be a lot less useful if the program is getting the idea that I don't have any weak words.