Pleased to report that epower's finding has corrected the issue on my setup as well (well done). Don't know why I didn't think of that

It does actually make a lot more sense than the theory I had about versions, etc. To echo 77_Scout's comment concerning the 'Run as Administrator' setting, I would agree it could/should be more clear...I found it OK, but perhaps not so obvious for all
Note this is only to say I've tested how to set priority and affinity with shortcut/command line settings. I still don't use these settings, and still do not find them recommendable on the whole. My research into the matter has thus far corroborated this position. That research is ongoing, and I'm happy to discuss it with anyone open-minded enough to listen.