haha- yes, but I appreciate any tips. I should have clarified what "ran some tests" means.
Specifically, I did check the problem files and they are square (this happened in two different oversized prints).
They are printed on Hahnemuhle German Etching paper (310 GSM)
1-I cleaned the rollers with alcohol and a lint free cloth (hoping the issue may have been that the coating from the papers I use transferred, and were now causing the paper to slip a bit while feeding). In the past when I've had a similar issue, this helped to resolve the problem.
2-I ganged up 6 smaller files, (approx 16x20's) into one large document and stroked the edge (at 40"x60") so that I could then measure the individual printed images as well as the ganged 40" x 60" printed edge. (this was both in an effort to see if smaller files are shifting as well as to print a 40x60 image without wasting paper or ink. The result here was that the 40x60 stroked edge was indeed off square, but the individual files were off a negligible amount. This says to me that yes, the prints are all shifting, but it's cumulative, so that on a 16x20 it's not noticeable, but on a 40x60, it is an issue. MAINLY it's an issue for this client because the print is being matted and framed with a reveal, meaning that the mat doesn't go to the printed edge, rather it 'reveals' a bit of paper before the mat window begins. So, in this case, the 5/16" is a major issue for the framer and client.
I'm at a loss what to tell them. I wonder if this is within epson's margin of error?
Has anyone else faced this issue?
Thank you for the replies!