Well, I think this has to be predicated.
If she kept her parents' address while she traipsed around in her early & mid-twenties, including while at B.U., and she hadn't officially registered somewhere else by say a lease, D/L, or Voter's Registration Card, then I have no issue with it and believe the board would be doing a disservice by yanking her.
Many kids I've known kept their permanent address at their parents' during that time of their lives, to simplify things and keep things stable for receiving official and important mailings. In fact, if she didn't do an official registration of the type I described in the paragraph above, I think the board would have a hard time even legally ascertaining her official address was not hers.
Now if she was registered somewhere else in one of the legal methods I earlier mentioned, then she may possibly have a problem.
As to your claim of "carpet bagger", I see that as a bit disingenuous. Oscaio-Cortez appears to have lived in NY City or the NYC area for pretty much all of her life. I see someone like Hillary Clinton as a carpet bagger, even though she may have gone through the motions to meet the technical qualifications to run her Senate bid. But a twenty-something kid, who lived in NY all her life? I just don't see it.