If you make a overlay with for example 2 pages over a
pdf with 5 pages, the pdf has on the first page the
second page of the overlay instead of the first page of
the overlay pdf.
The overlay starts with the wrong order because in the
method mergePage(COSArray array, PDPage page ) of the
Overlay class it is not considered that layoutPageSize
starts with 0.
But more see in the patch file I uploaded.