@Derrek, no, I’ve checked my Master Pages. I’ve become very adept at copying L->R, then immediately clicking the page number frame on the RH page, unlocking the R constraint, locking the L constraint, deselecting the frame, reselecting the frame, then setting the Left frames property (on the bottom pane) to 1pt. One also has to double-check the justification of the text within the frame.
Besides, it’s only overridden pages that display page numbers in the wrong places - all the other pages based on first/default etc. display just fine.