In what circumstances will the Attorney General deny that a copy of a Defendant's conviction was certified?

The prosecution in this case did represent to the court at trial that the copies of the convictions were certified. Defendant did not object to the admission of the copies or in any way alert the court that, contrary to the prosecution's representations, the copies were not certified. On appeal, the Attorney General does not argue that the copies were, in fact, certified but contends that defendant forfeited his right to object to any lack of certification. Defendant insists that a challenge to the sufficiency of the evidence is never forfeited or waived by failing to raise the deficiency at trial. (People v. Trujillo (2010) 181 Cal.App.4th 1344, 1350, fn. 3; People v. Rodriguez (2004) 122 Cal.App.4th 121, 129.)