I've got a source document with a single page (magazine style, left and right) and I want to create a document with two pages: left side, and right side of the document.
I duplicate the source page and apply cropping to the destination pages (50% right and 50% left).
It does not work, it will apply 50% cropping right and then 25% (50% of the 50%) left. The two pages in the exported document will look the same.
I've fixed it using the "copy module" of python. To use a "copy" of the source object instead of a "reference".
See my patched pdfshuffler (v0.5)