DS, if this is true they are even dumber than a rock. Their last try at faked documents in the GWB 60 minutes bit didn't teach them a lesson? OMG it is worst than I thought.

God help us
The layered updates to the original image are real. I can verify that. What I can't verify is the reason. Most of them seem to simply darken sections of the certificate that were fairly light, but I'm not exactly sure.
The other possibility is that this isn't really a scan and instead a conversion from another file type... but I can't think of any file formats that would store an image in such a way unless it was to account for edits in some way. Besides, the turned corners sure make it look like a copy from a large book.