I then attempt to take the survey in Student View as a Test Student, resetting the Test Student before I begin.
When I complete the survey, I leave Student View and go to Grades, click on the Test Student's quiz, and open SpeedGrader.
The results shown in SpeedGrader show all the correct answers, but in several places show more than one answer. I took the survey myself as Test Student, so I know I responded to each dropdown only once. Where are these phantom answers coming from?