I’d like to say that the image helps clarify the problem, but actually… it’s really confusing! I’m not sure why those would not appear.

Does it work in other, new documents?

Hi Jeremy: The best option is to just give up all hope. ;-) The second best option, of course, is to only add or remove an even number of pages at a time.

The third best option is to get clever with a combination of primary text frames, styles that have horizontal alignment “away from spine” or “toward spine” and carefully set up anchored objects based on spine alignment.

The fourth best option is this script that Ole Kvern wrote some years ago (Ole will be at CreativePro Week!)
https://creativepro.com/move-every-object-on-every-page-toward-or-away-from-spine.php

I answered on the Private Member forum. Those are indicators of an animation effect. :-)

You probably need to use Radio Buttons.
There are some good tutorials on creating interactive PDF files at LinkedIn Learning/Lynda.com (including one that I did). Do you maybe have access to that training?

If I understand correctly, you can probably set the Left Indent to a positive number (such as 3cm) and then the First Line Left Indent to a negative number (such as -3cm). Does that work?