The idea that because early money was on NE means that the final books will be out of balance is simply nonsense. That is why the line moves, to get it back in balance.
This risk that Vegas created for themselves is not that NE wins, it is that the game ends at +- 1 point and they middled themselves. Still not a huge issue, I seriously would doubt the cash lost to net middle action amounts to anywhere near the overall vig.
Also, the size of the move is a little deceptive. Any move across 0 has to be discounted by the impossibility of a 0 result.