Not sure how AU status is affecting her score. Regardless, she should absolutely get a no annual fee revolving account (or two) in her name to build credit history. Perhaps a USAA Visa/AMEX credit card and a Discover card.
Creditors can obtain listings from the CRAs of names and addresses of consumers who meet certain specified screening criteria.
The so-called promotional offers for credit that are then sent to consumers on the listing screen out any consumer who does not meet their stated criteria. Offers sent based on a listing obtained from a CRA are then requried to be "firm offers for credit" under the FCRA that must be honored if the consumer applies and is found to still meet the criteria set forth in their request for the listing.
If the creditor wishes not to send firm offers to consumers whose files include AU accounts, that could be one of the screening criteria in their request for a listing. Consumers with AU accounts mean that their scores are not based soley on their own prior history, and thus a creditor might not wish to offer credit until they can review a score that is based only on the consumer's own history.
Thus, having AU accounts could be a basis for no longer receiving promotional offers for credit that were being sent prior to addition of AU accounts to the consumer's credit file/report.