Evidence From Josephus and Philo That There Were Occasions When Converts Were Not Circumcised

So I was reading "Earliest Christian History" (Michael F. Bird and Jason Maston) and saw something interesting in an essay entitled "The Incident at Antioch".  The author provides evidence that there were occasions when converts to Judaism were not circumcised (at least not immediately):

"[Circa 44-46 C.E] a certain Jewish merchant named Ananias persuaded King Izates of Adiabene to convert to the Jewish way of life based on the Law (Josephus, Ant. 20.35).  Yet later when Izates wanted to be circumcised in order to be 'assuredly Jewish,' Ananias persuaded him to refrain from the practice, well aware that his subjects would resent a Jewish ruler.  Ananias informed Izates that, "zeal for the traditions of the Jews was superior to being circumicsed' (Josephus, Ant. 20.41).  The narrative in Ant. 20.17-50 assumes the normality of circumcision for male converts, though the grounds for foregoing the ritual in Izates' case were exceptional as a matter of political expediency.  Sometime later a Pharisee named Eleazar persuaded Izates to be circumcised in the end.  Still, the incident shows that there were occasions when converts to Judaism were not circumcised [emphasis added]. To this we can add evidence from Philo where the necessity of circumcision by converts seems somewhat ambivalent (Philo, QE 2.2; Migr. 92)."

This is merely an interesting selection of evidence.  I'm not suggesting that this is good evidence (however it does come from the prestigious series: Wissenschaftliche Untersuchungen zum Neuen Testament).  And I haven't yet examined the Philo references.