Yes. Two reports were filed by NaNoWriMo, to the FBI's National Center for Missing and Exploited Children's Cybertip line, which is the hotline that the FBI recommends calling for these kinds of claims. The first was filed on November 5 by former NaNoWriMo staff, via webform. The second was filed several weeks later by a Board member, who followed up twice after having placed their initial call.
The Board member asked, during their second follow-up call, whether NaNoWriMo was entitled to know the case's status or of any outcomes that stemmed from the complaint. We were told frankly that closing the loop with the complainant was not part of the process.
We have not been subsequently contacted by this or any law enforcement agency in relation to this claim or any other matter and we have no reason to believe we're being investigated.