Powerpoint: individual slides printing upside down

Hoping someone can help. I'm trying to print a presentation duplex and some of the slides/pages are printing upside down, while others are showing up fine. The duplex approach is to print landscape, flipping on the long slide, but when I reach slide 4 in the print out, it's flipping on the short side. Does anyone know how to resolve this? I'm using Powerpoint for Mac v 15.27.