Size is a good place to start.
The machines were fairly accurate, but depended on the operator to set them. 1/8 difference wouldn't be the machines fault.
After size it's about the quality of the edge. The sort of cutter usually used would leave a particular look to the edge, a slight taper usually on the front, and a slight ridge on the back. If the blade was newly sharpened it leaves less trace, if it was dull the results are more obvious.
I have a couple cards that wouldn't grade, but are factory cut. One was too small, the other had cuts that were too rough top and bottom. With T206 SGC seems more lenient side to side than top to bottom since one that was more narrow than another was short graded ok.
While I wish they'd recognize cards that are factory but undersize or oddly cut I can understand why they won't. It just wouldn't work to have a bunch of stuff out there where people only look at the size and assume trimming.
Odd cuts can happen if the paper is damaged or something else odd happens.I can only imagine the debate if this one ever got slabbed(Yes it's factory!)
Steve B
