A class-action lawsuit had accused the social media network of allowing third parties, including Cambridge Analytica, to access users' private data.
The latest case follows complaints by privacy campaigning group Noyb that Meta's three apps fail to meet European Union's strict rules on data protection.
The data behemoth has been implicated in several human rights abuse scandals, and activists critique the secretive deal and its ramifications for the public.
In a quick turn-around, WhatsApp claims that user concerns are based on misinformation while failing to address its past history of sharing data with Facebook
Normally, the Federal Trade Commission refuses to comment on its probes, but it took the unusual step of confirming a "non-public investigation" into Facebook over whether it mishandled private data.
Subscribe to our Youtube channel for all latest in-depth, on the ground reporting from around the world.
Copyright © 2023 TRT World.