A family of Microsoft word processing software products for creating web, email, and print documents.
Charles, thanks for the reminder. With all this, which I have found to be confusing, I had forgotten to do that test.
It works - there is no header inserted.
For info: When I went to change that setting it was at 12.7mm (same as the margins).
It hadn't caused a problem on PC but was causing a problem on Android. I still can't understand why Word for Android inserts a header (_yes it does_) to compensate for a margin conflict, but it does. I remain convinced that Microsoft should be aware of this as a probable issue for the developer pipeline.
This morning I was wondering whether there is a conflict between the desktop and mobile normal.dotm files even though that still wouldn't explain the insertion of a header. Now we know it's the margin/header space conflict which causes this to happen. I don't know the internal working of OOXML, but obviously Word for Android handles the conflict in a particular way while the desktop version of Word 2016 either considers that there is no problem or ignores it.
I maintain that, because Microsoft is pushing its marketing along advanced collaboration (see the latest changes in Word 2016), this will be an issue for other users in the future if it is not dealt with. As I said, I don't find any great need for this sort of collaboration (although maybe my next role will call for it, heaven forbid).
Good on you, Charles, for reminding me to do that test!