That would be congruent with the dropshadow displaying on the "You Should Use Both" text in the (presumably) PowerPoint-rendered one that is masked correctly. It doesn't seem to appear in the other.
EDIT: Also, on the US-zoomed/masked one, it makes the ellipses line up correctly with all the cable landings at the coastlines. I'm now sold that these differences are just PowerPoint-specific renderings.
Fits perfectly with the "different software" idea. Pages, Google Docs, OpenOffice and even different versions of Office produce different results with the same PowerPoint.