This is Win 7 which is my main development platform on my workstation, as well as on the workstations of perhaps a
billion other human beings on the planet Earth.

This however
may be due to the OS differences. Do you want me to switch on my W10 box and check? At any rate, something must be done with it under Win 7 and 8/8.1. Not all of us are so fond of extreme diving as you are, my friend.

I don't see my embedded OR orb, it isn't visible at all, so I can't tell you if it's dithered in OR or not for me. Not with this particular file. I'll remove all other images so that I can see the orb at least partially and then I'll tell you if I'm able to see a non-dithered original PNG in OR under Win 7 at all... But I need to go back to XP to re-save the modded file correctly in MS Word.
Stay tuned in the mean time.