I just did a 10 lesson session and only 4 items were removed from the lesson queue. So I tried to do it again, and go straight to the next lessons this time. Wanikani showed the new ones but if I open it in a different tab or go to summary the 6 lessons that I just did still stay in the lesson queue.
These are the lessons that caused trouble:
I just tried to do them again
But when I finished the lesson session the summary was still empty