OMP 3.1.2 - Chapter PDF will not display

I have encountered an issue in more than one OMP 3.1.2 installation where I add a publication format for a chapter and upload a PDF file for the chapter, then create a catalog entry for it, but on the published book page the catalog entry appears with no chapter PDF file link below it. I think I’m following the right steps and I wonder if this is a bug in OMP 3.1.2.

Are there any users of OMP 3.1.2 who have successfully uploaded chapter publication formats and made the file links available on their site - since upgrading to 3.1.2?

If yes, can you think of anything I’m doing wrong to explain why the links do not appear?