Job Posts not expiring

We’ve been setting expiry dates on the jobs in our list but when the day rolls around the expiry date seems to automatically update. The jobs aren’t being removed from the list on this page… https://www.ninethirtyeight.org/vacancies/ but the link on this page is eg. https://www.ninethirtyeight.org/?post_type=job_listing&p=12398 – that’s saying it’s expired but, as I say, it’s still showing on the front page.

Any ideas? Could it be a plugin conflict?

The page I need help with: [log in to see the link]