Text box text reflows when whole box is copied

[Rob the Slob]

Can anyone explain how text can reflow simply when copying a text box and pasting it? See screenshots. Maybe there's some default paragraph setting someplace that's causing this, but I couldn't suss it out. I'm not resizing the box at all. Just selecting, copying, pasting. Also happens when I use the Move command and hit copy—and not moving it at all, actually, just letting it paste on top of itself.

I need a genius . . .

[Michael Bullo]

Just want to confirm that you don't have anything with Text Wrap applied to it near your text box?

[Rob the Slob]

That was one of my first guesses. No, that's not it.

As I recall, something like this has happened to me before and that time it had to do with different paragraph composer settings between two documents. This phenomenon happens, though, within the same document.