wp_link_pages displays links incorrectly in preview?

I am experimenting with having paginated single posts. I had one post in draft with several <!–nextpage–> shortcodes, and added wp_link_pages(); to the content.php. It displayed the links fine, and they seemed to be working in preview, at first. But after a few more edits to the post, they suddenly seemed to stop working. Apparently the HTML generated the following link for page two, for example:

<a href="http://www.{site}.com/?p=29941%2F2%2F&preview=true">2</a>

I’m not sure whether this is different from what it was generating before we noticed it screwing up.

As a test, I made it live, and the links seemed to work correctly, generated with the permalink format. Then when it was unpublished, the links went back to the above.

Does this function simply not work in preview? Has anyone else noticed this?