Quizzes show as in-progress if the quiz or browser window was closed during the first time the quiz was attempted. Even if it is completed on a second attempt, it will not overwrite this initial status. Quizzes are designed to be completed all the way through the first time they are opened.
The good news is this has NO effect on being able to finish the course. Course completion is only dependent on whether or not you pass the final exam. Quizzes are just there to help you study! If your HR department requires you to show that you completed all assignments, please let us know, and we can help!