Lesson subsequent attempts not showing as completed in lesson reports but log report shows it has been

I use MoodleCloud.

Some of my students have redone a lesson (activity) which has questions included and the retake is showing as not completed.  I have (with their permission) signed in as them and it is showing that the new attempt has been started but nothing has been completed.  When I run a log report I can see they have fully completed the lesson i.e. answered the questions and ended the lesson.  

This error does not happen every time a student re-attempts a lesson.  But it is happening.  I have video of my screen when I logged in as the students showing that the reattempt is at the first page of the lesson with nothing completed and I have the log reports showing that this is incorrect.  I am happy to share these as I would like to know why this is happening and how to avoid it.  

The grades settings are correct (based on the moodle.org forum searches I have done).

Looking forward to resolving this issue

Michelle