New words in lesson practice
I used to do the lesson practice on the home page and it would only cover the words I had been already introduced to. Now it is coming up with new words that I haven't seen yet. Is this a change?
I'm looking into this... are you having problems with "Lesson practice" (the home page), or "Skill practice" (on a particular skill page), or both?
Just to be clear: you are saying you get new words highlighted in gold in your practice sessions? If so, that's a problem and I'm trying to figure out why (it could have to do with skill tree changes in prep for this week's iOS redesign and next week's language incubator).
BUT... if they are highlighted in blue or not highlighted at all, then you in fact have already learned them... it just may have been weeks or months ago. We made some changes to the spaced repetition algorithm last week (http://www.duolingo.com/comment/878880) that could be digging up words you forgot, even though Duo thought you'd learned them really well.
this is happening to me. I am getting words in practice (click on the "strengthen skills" button) that I have not learned ever. they appear in blue, as if I know them. then after I have done the practice these words are added to my vocabulary list but I have not seen them in any lesson. I redid all the lessons recently because of the changes. I noticed some new words have been added and i noticed some words that I had learned were missing. but I am sure that I never learned some of the words that appeared in my practice session.