Are all elements: InDesign document, placed graphics, and swatches all set to the same CMYK color mode? Especially objects overlapping other objects? Can you try making an InDesign version where you set the Transparency Blend Space to RGB, and can you try placing all images and swatches as RGB? That would be preferable (though not absolutely necessary) for an interactive PDF which would be RGB flavored.
Hi, and thanks for your help. That would be a bit of a faff, as I have set the whole doc up for export as a Pass4Press compliant document for professional print. However, the client also wants a navigable PDF created from the same doc. Because of the length of the document, I don't want to have two source docs, as that would be a revision control nightmare.
However, I've been playing around with the master pages, as it is items from the masters that are being rendered inconsistently. It seems odd that one master can be rendered differently on various non-overridden pages.
Guess what? I just tried disassociating the items from the masters (Override All Master Page Items) and tried again. Now, although I now have lost the benefit of using master pages, it does actually render properly and consistently now! Go figure. Must be one of those freaky little bugs. It would be cool if this could be fixed, but at least overriding masters seems to be a workaround.
Hopefully, my document is approved, and I can export the final Press PDF, save the doc, Override All Master Page Items, export the interactive PDF and not save with the disassociated masters…
Thanks for all advice and hopefully this will help someone else, or trigger one of the devs to look into this odd bug.