22) Why do Protestant scholars recognize the early Church councils at Hippo and Carthage as the first instances in which the New Testament canon was officially ratified, but ignore the fact that those same councils ratified the Old Testament canon used by the Catholic Church today but abandoned by Protestants at the Reformation?

There is no self contradiction, Sola scriptura does not ignore extrabiblical data which might assist in knowing the truth in scripture, but that material is never allowed to contradict or diminish in any manner, the inerrant Word of God.

Here is why Protestant scholars reject what was wrong in their decision:

Local Councils of Hippo and Carthage in North Africa were influenced by Augustine, the most significant voice of antiquity who accepted the same apocryphal books later canonized by the Council of Trent. However, Augustine’s position is ill-founded: (1) Augustine himself recognized that the Jews did not accept these books as part of their canon (Augustine, 19.36–38). (2) Of Maccabees, Augustine said, “These are held to be canonical, not by the Jews but by the Church, on account of the extreme and wonderful sufferings of certain martyrs” (Augustine, 18.36). On that ground Foxe’s Book of Martyrs should be in the canon. (3) Augustine was inconsistent, since he rejected books not written by prophets, yet he accepted a book that appears to deny being prophetic (1 Macc. 9:27). (4) Augustine’s mistaken acceptance of the Apocrypha seems to be connected with his belief in the inspiration of the Septuagint, whose later Greek manuscripts contained them. Augustine later acknowledged the superiority of Jerome’s Hebrew text over the Septuagint’s Greek text. That should have led him to accept the superiority of Jerome’s Hebrew canon as well. Jerome utterly rejected the Apocrypha.- Geisler, N. L. (1999). Baker Encyclopedia of Christian apologetics. Baker reference library (30). Grand Rapids, Mich.: Baker Books.

When Bible Christians recognize extrabiblical statement as correct, it does not follow everything else they said is correct or has authority......they and everything else they say could be wrong. For example, Paul cites Pagan poets and philosophers (Acts 17:28; 1 Cor. 15:33; Titus 1:12), but never as Scripture, and never implying anything else they is correct or authoritative. Nor can any extrabiblical tradition or data contradict the Bible, our final authority.

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The times of this ignorance God winked at; but now commandeth all men every where to repent:

Behold, I stand at the door, and knock: if any man hear my voice, and open the door, I will come in to him, and will sup with him, and he with me.-kjv