They likely do not have a NYRR rule for this. Everyone incorrectly thinks road racing is simple and meaningless and does not need a thick rule book like the IAAF has for track.
Without a clear rule, and without a protest, likely no DQ, BUT what she did was unethical.
She veered from a running a straight line to block the other runner's path;
She only extends one arm up. That is a weird way to celebrate or break the tape.
She acted a little guilty after the win. No huge celebration or high fiving fans. She looks sheepish and subdued, esp after setting a big PR. Maybe she was just exhausted and did not realize what she was doing but she still impeded the other runner.
It does not matter what happened earlier in the race. Two wrongs do not make a right. If you are racing against a known cheater, you do not have the right to cheat yourself.
This was not clean and fair racing on her part, I was a fan of hers but now will not be.
What will New Balance do? Likely ignore it, but they should question it,