Even a court of subordinate jurisdiction is permitted to enter into the question as to whether the judgment of a superior Court was obtained by playing fraud on the later Court because such a judgment is nullity and is required to be treated as non est.
Union of India and others v. Ramesh Gandhi, (2012) 1 SCC 476,
A wrong decision cannot be a ground to repeat a mistake.
It is right to question the the legality of the judgement but should be very very cautious.