Old Words Refuse to Strengthen?
I did some German with Duolingo some time back and recently picked it up again. I'm really enjoying it but I do have one annoying issue. A bunch of words--they look like they mostly come from Food 1, Plurals and Animals 1--insist that they were last practiced "three years ago" and are "overdue". These words have since appeared in other lessons and practice but have never updated. And now it looks like some words from Food 2 may be got stuck in the same situation even though that is a new lesson I just did last week and have reviewed several times since! This does not appear to affect basic functionality but it would still be really nice to have an accurate representation of my vocabulary and its status.
Is this a known issue? Can anyone suggest a way to "unfreeze" these words?
I used to use the Android app exclusively and not only did I notice the problem you're describing, but my fluency score was stuck and in fact decreasing. I switched to the website and my fluency zoomed higher in three days and I've been seeing words I haven't seen in a long time. I can't run the Words page without my tablet locking up to see how those "old" words are, but I'm guessing that has cleared up now that I use both regularly. My tree has been golden forever, but now occasionally I'm seeing the odd section get ungilded as well. So, that may help. I get the feeling if the word is incidental to the point of the lesson, it doesn't get counted as re-practiced.
Update. Found my oldest words were all food or animal related. Went and did those lessons again and again. No change. They don't show as practiced. I'm wondering if this is related to testing out using the app when I started. Except it seems to be the same lesson groups mentioned in the OP. It seems any "weak" word shown as not practiced in over a year cannot be flipped to "just now" even by taking practice lessons repeatedly in the lesson it shows as being presented in. Newer weak words will show as just practiced if you go to that lesson, but anything marked as a year old is frozen.