Can birthparents contest a finalized and proper adoption?

In Texas, even after finalization bparents can ask them to set the decision aside. I don't know what criteria is used, it may be only for bfathers whose rights are terminated by publication and not by them actually signing TPR. So, even a finaliztion is not final! Gotta love the court system. And, as long as there are lawyers willing to take on those clients, there will be aparents put through the wringer. Our lawyer assured us that even if that happened, it is unlikely that the bfather would win, but that doesn't keep it from draining our bank account!