I can confirm that if I add a final line \iex the end, then I see some odd behaviour too - could you describe yours in more detail? I’m getting a page with a line like:
%%%%% Back Matter PDF file(s) get included here %%%%
Is this what you’re getting?
I don’t get it if there’s an empty \p after the \iex line, so that’s one work-around.
As to the cause… most intro paragraphs cause a swap between double and single column. \iex gets some slightly special treatment because someone asked for it to not trigger a two-column to one-column transition, so the code has been asked to not trigger column swaps when iex gets met.
Without having seen your issue, I finally got round to implementing a slightly nicer way to respond to people having introductory paragraphs in the middle of their text, so that exists in test code… I wasn’t planning on merging it since we’re very close to releasing 1.6, but maybe I should.
But I’ve no idea why that special treatment ought to cause the issue I’m seeing, although I can confirm that making it behave like any other intro paragraph marker makes the problem go away… it’s very puzzling.
