PDF shows more content in preview than when actually opened

A client sent me a pdf file of some artwork. When I go to preview it, I can see that there should be more shapes and text, but that is not visible once actually opened.

Importing the pages as links makes no difference.

I've also tried flattening the transparency, releasing the clipping mask, but nothing is showing that other content. 

When the file is opened through acrobat, it also does not show that extra content.

Is it actually present in the file?

previewopened