PDFs looks weird on Mac Preview & Mac Mail

When I export a pdf from Indesign in high quality print setting, it's displaying photos weird when I look at it in preview or attach it in mail. Doesn't matter if it's grayscale or cmyk, same results.  Seems like it may be a transparency issue, I have a slight feather on this one; I've seen it do it with drop shadows before too. I remember this used to happen many years ago but then seemed to fix itself. Anyone have a suggestion on how to fix now? It's distracting when sending proofs to customers.

(Ignore the yellow boxes in attachment - I just did that for privacy)