Reply To: Baffling Master Page Dilemma: Elements Shifting on Content Pages

Barbara, are you saying you have objects moving up or down on the page? Or are they just shifting left and right?

It’s important to note that InDesign has a known feature (not a bug) where objects on master pages may appear to shift left or right when you add a single page in the middle of a facing-pages document — because the left-hand pages are turning into right-hand pages, etc.

This has been discussed for 20 years, including these posts:

Master items reappear after inserting new page

and

Move Every Object on Every Page Toward or Away from Spine