Allowing Rectangles with additional elements

I've come across some pages in a large PDF that have some additional, non-numerical elements at the end of the MediaBox rectangle array, e.g. 

/MediaBox [0 0 612 792 5 0 R 6 0 R]

Trying to read such a structure with PDPage.getMediaBox() throws an exception trying to construct the PDRectangle at this line

I'm not sure if this strange case should be treated as a file issue, or if should be supported by slicing / shortening the COSArray prior to trying to convert to floats. Acrobat Reader shows the pages without complaint.

The original PDF was produced by Foxit PhantomPDF Printer Version 7.3.9.0803.