Certain pages don't have title tag and lose parent structure

Hello!

I have a very strange issue with specific pages on a site I’m working on.

Here is the site: https://www.about-face.org/ and one of the specific pages I’m having trouble with is https://www.about-face.org/gallery-of-offenders/top-ten-offenders/5-2/

The problem is that the page has a blank title tag (so the page title doesn’t show in the browser header), and also the breadcrumb (Yoast’s plugin) is blank. It’s as if the page has lost its parentage!

This issue affects ONLY the page entitled “5” under each of the main gallery headings (eg: https://www.about-face.org/gallery-of-offenders/archive-of-offenders/gallery-8/5-2/ and https://www.about-face.org/gallery-of-offenders/archive-of-offenders/gallery-7/5-2/). Pages 1-4 and 6-10 under each gallery heading are fine.

I can’t figure out why this is happening, except to think that perhaps the database is corrupted? It’s weird that it only happens on page 5 each time.

Can anyone help? Thank you!

Tessa