https://mpsocial.com/t/lvl2-megathread-reducing-inauthentic-activity-on-instagram-2018-11-19/53963
And more if you search. Ask her to include a screenshot or anyone else who gets them. People freak out and exaggerate what they received from IG.
Even regular people are getting that message so there’s a good chance it’s just a BS notice. She could have used Hootsuite or planoly or something along those lines in the past. Anyone can get that message honestly.