[Publisher] Transient gray outline around images when exporting to PDF

[Vex]

I am working on a project to convert a whole bunch of PSDs to an ebook, and I'm using Publisher and the data merge feature to create Publisher documents for each chapter of the book using the PSDs, which I then export to PDF with no image compression or rasterization. Some images in the master PSDs are showing up in PDF readers with a transient gray outline that sometimes moves or disappears depending on how far you zoom in when viewing the PDF. The lines aren't printing, so I don't think they're actually part of the document, but I'm seeing them in multiple PDF viewers.

 

[Lee D]

Are you seeing any reference to these frames on your document within Affinity Publisher?

[Vex]

Nope. If I open the PSD to edit within Publisher (i.e. not with Photoshop), there's no indication these lines exist. Some of the image layers do have transparency, if that matters.