All right, let us know.
Nevertheless, while looking at your screenshots, I'm very surprised you didn't find any differences between your object styles, just like Bob suggested.
My guess is that your [Basic Text Frame] object style differs between the 2 docs, and gets in conflict. This would explain that Blue rounded-corner stroke that shouldn't be there and generates the Text in excess (since your frame probably fits the content).
Moving pages instead of copy/paste might be an acceptable workaround, but definitely won't clean up the conflicts (object & paragraph styles) that I would definitely recommend you try to get rid of...
I gave up figuring out the problem and manually fixed each text frame.
Thanks for the invaluable lessons ... I'm still learning ...