Lessons which I have already completed now show greater than zero new words. When I click into the lesson I see that a few random short sentences (2 words) have been highlighted as blue.
It is an odd bug considering that usually when we see new content for the first time it is the words which are highlighted as new, not the sentences. I’ve never seen.
I still see that completed lessons have >0 new words. When I click into the lesson, the entire ribbon at the top shows as green. When I page through the lesson I cannot see any blue words.
I was also having this problem. Having given up on a fix, I was able to remove the problem by removing the lessons from my list and then re-adding them; they showed up with zero new words.