I can confirm that when following the steps in my original post, no ghost data is displayed on the front end within a regular while (have_rows) loop.
I wish I had mentioned in my original post what steps to take to get the ghost data to display on the front end, but six months later I’m afraid can’t remember!
Perhaps, as John suggests, there was some other factor at play. Perhaps I was accessing data outside an ACF loop. Or maybe the behaviour of ACF has changed since February to fix my initial problem.
Hopefully Michelle’s testing will be able to shed some light.
