I managed to download a PDF file (from the White House Web Site) and was looking at what you are looking at.
PLEASE TAKE A LOOK AT THIS.
1) In Adobe right click over the document and left click “Marquee Zoom”
2) Now scroll up and down the document (with wheel on your mouse). Look at what you were looking at.
You can clearly see it it in the name Barack (how the R sticks out), and then scroll down the document and you can clearly see the white out with the type over.
That is consistent with Adobe Acrobat separating text from a background image for compression. The document appears to be authentic. The original record was copied on microfiche which was then used to print the new certificate which was then signed by the registrar.