Don't want to give up, but...
Love duolingo and want to complete my tree, but am facing 2 bugs which are really hindering progress.
My tree incorrectly says I have completed lessons in: objects, people, to be and object pronouns. I havn't even attempted those lessons.
My word strength from previous lessons never decays.
Don't want to move forward until those are fixed, but really want to keep learning. Feel a bit stuck
Sometimes you'll encounter vocabulary words in sentences before you get to the lesson they're attached to. So when you reach that lesson later, it'll appear as though you've already made some progress, even though you haven't even started it yet.
I'm not sure how long you've been using Duolingo, but it takes some time for word strength to start to decay. I noticed the same thing at first, but it did sort itself out fairly quickly.
Hope your studying goes well from here on!