The federal district court was recently called upon to review one of claims that a borrower can "quiet" a mortgage based on defects in the subsequent assignment or securitization.   Even though the court didn't address the ultimate issue, granting leave to amend, it is interesting reading. 

Even where a borrower is successful with this tactic, my understanding is that most underwriters are hesitant to insure over a recorded (albeit quieted) mortgage.  Please discuss with your underwriter.