At the top of portrait format or the side of landscape was a series of lines extending about 40mm into the picture. His first thought was that the camera was at fault. Then, maybe, the SD card reader. Neither was the case so he made an appointment at the Genius Bar to see if Apple’s experts could pinpoint the problem.
I’m also seeing this on large jpegs from my Olympus OM-D EM10 imported via Lightening SD adaptor into Photos on iOS on my iPad Pro 9.7″. This indicates it is not exclusive to non-Pro iPads.
Once the images are in Photos for iOS (unaffected by corrupting lines at this stage), exporting them to shared photo streams on iCloud introduces the horizontal lines.
After the original images have synced to iCloud, if I share the photos from Photos for OS X on my MacBook Pro then the lines are not introduced, so it seems to be a rendering problem on the iPad Pro 7.9″ and others, perhaps in Photos for iOS itself.
EDIT: Interestingly it doesn’t seem to be the actual rendering/exporting process in Photos for iOS, as emailing a copy of a photo to myself in various sizes does not introduce the horizontal lines either.
I’m thankful that at least one other person has experienced and reported this; when time allows I think another trip to the Apple Store is required (this is my second iPad Pro already).