[messierhunter]

As I suspected, it’s entirely a google processing artifact. It’s not in the original image at all. Here is the full resolution, original image. I took the liberty of converting it to a png file so that most people can open it:
http://dropcanvas.com/bv99x
Here’s a crop from the original overlaid on top of the crappy Google version of the same image projected onto their moon mosaic:
http://imageshack.com/a/img822/8360/b1z.gif
The “perspective” shifts because google moon is projecting the image onto a 3d model of the terrain and rendering it, using the image as a texture. The raw original image does not contain those artifacts, and is in fact much higher quality anyway as you can see.

Mystery solved.

[ETL]

As I suspected, it’s entirely a google processing artifact. It’s not in the original image at all. Here is the full resolution, original image.

Thanks. Nice work.

[Errant]

Mystery solved.

Well, it was fun while it lasted... ;)

jk, thanks for your hard work!