But the idea that they kept sacrifices is confounded by the many statements in the Clementine Literature which is generally thought to come from this/these groups. As Jews didn't continue to sacrifice the fact that they did not sacrifice wouldn't have made them seem less Jewish.
But Epiphanius says that the origin of these kinds of Jewish Christians came "after the fall of Jerusalem" (Pan. 30.2.7). These were the ones he says used the Travels of Peter and the Ascents of James, which are thought to have been incorporated into the Clementine literature (Pan. 30.15.1-3 and 30.16.7).
The other ones, in chapter 29, kept the entire Torah and went back to the time of the disciples.
For these people did not give themselves the name of Christ or Jesus' own name, but that of 'Nazoraeans.' But at that time all Christians alike were called Nazoraeans. They also came to be called 'Jessaeans' for a short while, before the disciples began to be called Christians at Antioch.
For they do not repudiate the legislation, the prophets, and the books which are called Writings by the Jews and by themselves. They have no different views but confess everything in full accord with the doctrine of the Law and like the Jews, except that they are supposedly believers in Christ ... They are perfectly versed in the Hebrew language, for the entire Law, the prophets, and the so-called Writings—I mean the poetic books, Kings, Chronicles, Esther and all the rest—are read in Hebrew among them, as of course they are among the Jews.
They are different from Jews, and different from Christians, only in the following ways. They disagree with Jews because of their belief in Christ; but they are not in accord with Christians because they are still fettered by the Law—circumcision, the Sabbath, and the rest.
This sect of Nazoraeans is to be found in Beroea near Coelesyria, in the Decapolis near Pella, and in Bashanitis at the place called Cocabe—Khokhabe in Hebrew. For that was its place of origin, since all the disciples had settled in Pella after their remove from Jerusalem—Christ having told them to abandon Jerusalem and withdraw from it because of the siege it was about to undergo. And they settled in Peraea for this reason and, as I said, lived their lives there. It was from this that the Nazoraean sect had its origin.