A bar appears over (and covering) the question or first answer in a quiz

I publish my presentation in HTML5. A rectangular bar often appears on top of the question (or the first response option) in my quiz. That bar does not let the viewer see the question or answer. If the user zooms or changes the screen then the bar disappears. The bar is nowhere to be found in the PPT slide. It happens in almost all my quizzes in different presentations. Using Office 2013 and Presenter 10. The PDF version does not have this problem, it is only in the HTML5.