Can't progress to next unit after attempting all questions

We have a group of 4 units followed by a quiz, then 4 more units and a quiz etc

On the exam units I've ticked "User needs to answer all mandatory assessments and view all pages in order to access the next unit" and the other 2 options are left un-ticked.

If user does first exam and answers all questions (some may be incorrect) he can't progress to the next unit even though he was answered all 10 questions from the previous unit.

For the moment I've un-ticked that option to allow people to always see the first unit after a quiz.