Hi TarynPierce!
Happy to share some insight on this!
The Activity Report tracks the total duration for the specific attempt, for all lessons viewed in the attempt. Unfortunately, there isn't a way to track the duration spent on each lesson.
Each record in the Activity Report shows the number of Lessons Viewed per attempt. So if the learner viewed Lesson One on the first attempt, and then viewed it again on the second attempt, then they may get a higher number of combined Lessons Viewed for all attempts than their total number of lessons in the course.
Please let me know if you have any more questions!