I completely disagree with your premise that playing the perfect game requires you to never move the same piece twice in the opening. That's just a guideline created by humans, and has nothing to do with playing perfectly.
I wouldn't call Ne2 a mistake - however, note that your knight is already developed on Nc3, so the computer is trying to maintain equality in the center by opposing black's rook. This develops the f rook to a natural square. I suspect that Rfe1 may in fact be objectively better - but if your plan is a kingside attack, I don't see anything wrong with Ne2.

Hi!
I just want to get your opinion in this (chess.com)computer-analyzed game of mine where I think the computer has inadvertently made a mistake of its own...
In the diagram, white has just moved 11.Ne2 which the computer tagged as (?). Now if you go to its alternative (which it says as the BETTER move) line, it has suggested moving the same piece TWICE in succession.
I am just curious if this is really how the computer thinks the game should continue or is this a glitch in the program.
You see I am of the impression that if computers are capable of predicting accurately the proper way to proceed with a game, shouldn't it be creating a line that does not move the same piece twice in succession???
Thanks!