Art is bleeding onto facing page in PDF

I have created a book with full bleed art on the left-hand page and no art on the right-hand page. If I create a pdf with crop marks and bleed, no problems. The pdf shows that the art is placed correctly and it trims were it is supposed to.

But if I create a pdf without crop marks or bleed, a sliver of the art from the left-hand page shows up on the right-hand page. The picture box is created at the right size and is placed correctly in InDesign, so I know that’s not the issue.

It also happens if I create a pdf with crop marks but without bleed. 

I create PDF files without crops or bleeds to submit to clients for approval all the time, and this problem has only occurred on this particular book.

You can see the issue in the attached screen grabs. 

What is happening?