My students lesson are marked complete when they haven't even started
Could somebody help? I tried to report the bud but the duolingo haven't answer
I've reported this bug on the Educator's Network, to get more eyeballs on it.
In the meantime, why don't you have your students send you screenshots when they get the "Congratulations" screen? I know it's a bit clunky, but I have my students do that when they complete my Duolingo Tinycards decks or do Duolingo stories (both of which don't register in Duo for Schools).
Another work-around is to tell the students that this is a glitch and that on your end, you see their true progress. If they hover over the lesson icon (under "assignments"), it will say how much of the assignment they've actually completed. Then, when they scroll down to it and click, it will also inform them that they haven't even started yet.