Looks like a pretty close one to me, Coach. Do they line up like that on every play? Or do they line up like that to gain an advantage when they pass block and move up 1/2 yard when they're run blocking? From this angle, the right guard and right tackle might be OK. The LT looks like he's not breaking the plane through the snapper's waist. Note, it also matters "when the ball is snapped" so does that snapper lift his butt and move it back even slightly right before the snap? If I have to ask questions like this in order to justify throwing a flag, I'm probably keeping it in my pocket. Curious to hear what other wing officials have to say about this one.
If a coach pointed this out to me in pregame, I'd definitely ask my wings to keep an eye on it. If they decide this is illegal, I think it's close enough for a "talk to them" the first time. As I said, if they are doing this to gain an advantage on passing downs and line up differently on running plays, that's a different story and deserves a flag.
“ART. 9 . . . A lineman is any A player who is facing his opponent’s goal line with the line of his shoulders approximately parallel thereto and with his head or foot breaking an imaginary plane drawn parallel to the line of scrimmage through the waist of the snapper when the ball is snapped.”