I had originally filed this as a reopening of bug 54626 (comment 9 https://bugzilla.wikimedia.org/show_bug.cgi?id=54626#c9 ) as I was uncertain what had triggered it. Now I know. When I translate a wikipage with Google, that is when the forceHTTPS cookies are being set despite that breaking my preferences.
In case this affects things, at the time I do that, I am not signed in to Google, but I am signed in to Wikipedia. When I translate the webpage on Goggle that is when I first get the popup message:
You are centrally logged in as <username>. Reload the page to apply your user settings."
That also is likely when the fifteen unwanted cookies are placed.