Copy-paste into a primary text frame?

@MaradrX  I think where things might be going sideways is in how you’re using your Parent Frames. Usually, you only want one primary text frame per Parent Page. The rest of the elements up there should really just be running headers, footers, folios, and any page decoration or numbering.

When you start working with your actual content, you override that primary frame once on the first live page, then thread your text from page to page (or use Smart Text Reflow). That way, the structure and position of the text frames still come from the Parent Page. If you later adjust margins or resize the parent text frame, those changes will flow through all the threaded pages automatically, as long as you haven’t manually resized or moved the live-page frames.

If you instead paste text directly into multiple separate text boxes, you’re effectively detaching them from the parent system. That’s why any later updates on the Parent Page don’t carry through you’ve broken the link.

As @BobLevine  mentioned, InDesign’s behaviour here is absolutely by design, and once you work with it rather than around it, it becomes very predictable. And @Mike Witherell  and @davecourtemanche  are spot on too the workflow really shines when you plan your parent setup before loading in the text.

Changing layout structure midway is always possible, but it’s a bit like trying to move the foundations after the house is built. It’s worth thinking of it as finishing at the beginning spend the time getting the Parent Pages right first, and everything that follows becomes a breeze.

Hope that clears up what’s happening it’s not a bug or an oversight, just InDesign doing exactly what it’s meant to. Once you get used to threading and working with Parents, it all clicks beautifully into place.