TSA is rolling out the “Credential Authentication Technology” (CAT) tool broadly. They check both the authenticity of the document and whether the information matches what they have for the passenger’s ‘Secure Flight’ data in their reservation (name, date of birth, gender). If it isn’t a match, the passenger is sent over to the airline to get things sorted.
However since passengers no longer need a boarding pass when this system is in use, they’re proceeding past the security checkpoint without first checking in for their flight