Why do circles rotated 45 degrees in PowerPoint slides not appearing in PDF?

I am using Acrobat XI Professional and PowerPoint 2013 in Windows 8.

I have two PowerPoint slides. One slide is a filled-in circle. The other slide has another filled-in cirlce that is rotated 45 degrees. When I convert the PowerPoint presentation with the two slides to PDF, the circle that is rotated 45 degrees does not appear in the PDF document. This is true for all circles rotated by a factor of 45 degrees with the excpetion of circles that are factors of 90 degrees.

Does anyone else have the same experience? Is this a bug in Acrobat?

Here is the PowerPoint presentation: http://www.aespen.ca/AETests/TheCaseOfTheMissingDot/Presentation1.pptx.

Here is the PDF document converted from the PowerPoint presentation: http://www.aespen.ca/AETests/TheCaseOfTheMissingDot/Presentation1.pdf.

Thanks. - john