It's not just you - I've had a lot of paper feed problems for larger sheets (13"x19") with the 3800 & 3880. Often it won't feed, and, when it does, it comes out significantly skewed. This happens with both the main multi-sheet feeder and the rear single-sheet feeder. I've gone through at least three 3800/3880 printers, and they all had these problems.
I almost never had paper feed problems with my various earlier models of Epson printers. I'm starting to get very annoyed with the 38** line...
Lisa