Whenever I try and print a single image at A3, I seem to get a 1 - 2 inch margin on the left side of the image when printing to an Epson SC P800 printer. This is using OS X 10.11.3 and Lightroom 2015.4. This worked fine at the end of last year, and lightroom was last updated 13 days ago.
I have tried both borderless printing (including zoom to fit) and "bordered", but the issue remains. The image isn't shrunk but "cropped" on the right (with a slight margin circa 30mm when borderless).
If I print multiple images on the same page, then the print is exactly as I would expect, with a 30mm border on the left and right!