Chapter disappears on Compile

I predominately work on my my MacBook, but find my iPad useful for editing etc. I’ve recently compiled the full ms on the iPad, and found chapter 16 (out of 17) to be missing. It looks fine and normal in the draft, “include in compile” is checked, but disappears when I compile it! So I’ve tried compiling just that chapter, and all I get is a blank page (with the usual header) and the label 0 Words. All the others work as per usual. Any ideas? Should I clear the Dropbox cache in settings (one of the scenes is in the conflict file)?