Some posts not expiring

Hi,

I am getting a strange issue where some posts are expiring and some aren’t, the plugin is on version 2.3.1.1 and it has been working just fine up until recently. I’ve taken a look and it is enabled on the custom post type which has the expiry dates on there. The date and time format are displaying okay so I don’t think it’s that.

Anyone know how I can fix this?

Thanks