Paint color circles distorts in PDF view

This may be a bug. I am a color designer so I work with paint colors a lot. When I save the mood board as a PDF, come paint circles will distort and look oval instead. Steps to recreate. 1) Add a paint color image from the Paint Library 2) Crop to a circle 3) Save the board and Select to save the presentation as a PDF.

The result is that the PDF distorts some of the paint colors from a circle to an oval.