Some TOC chapter numbers missing at compile

I have a strange problem. When I compile my book my TOC (generated the usual way within Scrivener) is missing chapter numbers, but only for certain chapters. Here’s an example below. As you’ll notice the numbers for chapter 18 ‘The Ragged King’, chapter 24 ‘At Yazidi’s’ and chapters 26 & 27 are all missing. This contents page is in my ‘Front Matter’ folder, with ‘As Is’ unchecked.

Anybody have any ideas what might be going wrong?

Thanks…

Possibly you’ve excluded these items from having a title prefix or suffix, in the Title Adjustments compile option pane. Click on the gear button to make sure they aren’t checked off.