"Usually " bit not always.
If the identical same catalogue of books (canon) documented to be extant in 382 AD, 405 AD, all the way through 1546 AD (Trent) and continuing to 2018 AD (now) --- that is, 1600+ years of continuity --- is considered unsettled, it's you who have a problem.
How, how can you honestly deny the well-substantiated fact that it was not settled, that In reality, scholarly disagreements over the canonicity (proper) of certain books continued down through the centuries and right into Trent, until it provided the first "infallible," indisputable canon after the death of Luther.
Or do you define "settled" as meaning a majority but not binding view, with scholars of very high esteem able to disagree, without censure?
● Jerome (340-420), the preeminent 3rd century scholar rejected the Apocrypha, as they did not have the sanction of Jewish antiquity, and were not received by all, and did not generally work toward "confirmation of the doctrine of the Church." His lists of the 24 books of the O.T. Scriptures corresponds to the 39 of the Protestant canon,
Jerome wrote in his Prologue to the Books of the Kings,
“This preface to the Scriptures may serve as a helmeted [i.e. defensive] introduction to all the books which we turn from Hebrew into Latin, so that we may be assured that what is outside of them must be placed aside among the Apocryphal writings. Wisdom, therefore, which generally bears the name of Solomon, and the book of Jesus the Son of Sirach, and Judith, and Tobias, and the Shepherd [of Hermes?] are not in the canon. The first book of Maccabees is found in Hebrew, but the second is Greek, as can be proved from the very style.
In his preface to Proverbs, Ecclesiastes, and the Song of Songs he also states,
“As, then, the Church reads Judith, Tobit, and the books of Maccabees, but does not admit them among the canonical Scriptures, so let it read these two volumes for the edification of the people, not to give authority to doctrines of the Church.” (Shaff, Henry Wace, A Select Library of Nicene and Post-Nicene Fathers of the Christian Church, p. 492)
Some think Jerome later defended the apocrypha based on comments about Daniel, but which is countered here
● Athanasius of Alexandria (c. 367), excluded the Book of Esther (which never actually mentions God and its canonicity was disputed among Jews for some time) among the "7 books not in the canon but to be read" along with the Wisdom of Solomon, Sirach (Ecclesiasticus), Judith, Tobit, the Didache, and the Shepherd of Hermas. (https://en.wikipedia.org/wiki/Athanasius_of_Alexandria#New_Testament_canon)
Gregory of Nazianzus (330 – 390) concurred with the canon of Anastasius.
● The list of O.T. books by the Council of Laodicea (363) may have been added later, and is that of Athanasius but with Esther included. It also contains the standard canon of the N.T. except that it omits Revelation, as does Cyril, thought to be due to excessive use of it by the Montanist cults
● John of Damascus, eminent theologian of the Eastern Church in the 8th century, and Nicephorus, patriarch of Constantinople in the 9th century also rejected the apocrypha, as did others, in part or in whole.
● The fourth century historian Euesibius also provides an early Christian list of both Old and New Testament books. In his Ecclesiastical History (written about A.D. 324), in three places quoting from Josephus, Melito and Origen, lists of the books (slightly differing) according to the Hebrew Canon. These he calls in the first place 'the Canonical Scriptures of the Old Testament, undisputed among the Hebrews;' and again,'the acknowledged Scriptures of the Old Testament;' and, lastly, 'the Holy Scriptures of the Old Testament.' In his Chronicle he distinctly separates the Books of Maccabees from the 'Divine Scriptures;' and elsewhere mentions Ecclesiasticus and Wisdom as 'controverted' books. (http://www.bible-researcher.com/eusebius.html)
● Cyril of Jerusalem (d. circa. 385 AD) exhorts his readers “Of these read the two and twenty books, but have nothing to do with the apocryphal writings. Study earnestly these only which we read openly in the Church. Far wiser and more pious than thyself were the Apostles, and the bishops of old time, the presidents of the Church who handed down these books. Being therefore a child of the Church, trench thou not upon its statutes. And of the Old Testament, as we have said, study the two and twenty books, which, if thou art desirous of learning, strive to remember by name, as I recite them.” (http://www.bible-researcher.com/cyril.html)
His lists supports the canon adopted by the Protestants, combining books after the Hebrew canon and excludes the apocrypha, though he sometimes used them, as per the standard practice by which the apocrypha was printed in Protestant Bibles, and includes Baruch as part of Jeremiah.
● Likewise Rufinus:
38.But it should also be known that there are other books which are called not "canonical" but "ecclesiastical" by the ancients: 5 that is, the Wisdom attributed to Solomon, and another Wisdom attributed to the son of Sirach, which the Latins called by the title Ecclesiasticus, designating not the author of the book but its character. To the same class belong the book of Tobit and the book of Judith, and the books of Maccabees.
With the New Testament there is the book which is called the Shepherd of Hermas, and that which is called The Two Ways 6 and the Judgment of Peter.7 They were willing to have all these read in the churches but not brought forward for the confirmation of doctrine. The other writings they named "apocrypha,"8 which they would not have read in the churches.
These are what the fathers have handed down to us, which, as I said, I have thought it opportune to set forth in this place, for the instruction of those who are being taught the first elements of the Church and of the Faith, that they may know from what fountains of the Word of God they should draw for drinking. (http://www.bible-researcher.com/rufinus.html)
●Summing up most of the above, the Catholic Encyclopedia states,
At Jerusalem there was a renascence, perhaps a survival, of Jewish ideas, the tendency there being distinctly unfavourable to the deuteros. St. Cyril of that see, while vindicating for the Church the right to fix the Canon, places them among the apocrypha and forbids all books to be read privately which are not read in the churches. In Antioch and Syria the attitude was more favourable. St. Epiphanius shows hesitation about the rank of the deuteros; he esteemed them, but they had not the same place as the Hebrew books in his regard. The historian Eusebius attests the widespread doubts in his time; he classes them as antilegomena, or disputed writings, and, like Athanasius, places them in a class intermediate between the books received by all and the apocrypha. The 59th (or 60th) canon of the provincial Council of Laodicea (the authenticity of which however is contested) gives a catalogue of the Scriptures entirely in accord with the ideas of St. Cyril of Jerusalem. On the other hand, the Oriental versions and Greek manuscripts of the period are more liberal; the extant ones have all the deuterocanonicals and, in some cases, certain apocrypha.
The influence of Origen's and Athanasius's restricted canon naturally spread to the West. St. Hilary of Poitiers and Rufinus followed their footsteps, excluding the deuteros from canonical rank in theory, but admitting them in practice. The latter styles them "ecclesiastical" books, but in authority unequal to the other Scriptures. St. Jerome cast his weighty suffrage on the side unfavourable to the disputed books... (Catholic Encyclopedia, Canon of the Old Testament, eph. mine)
● The Catholic Encyclopedia also states as regards the Middle Ages,
In the Latin Church, all through the Middle Ages [5th century to the 15th century] we find evidence of hesitation about the character of the deuterocanonicals. There is a current friendly to them, another one distinctly unfavourable to their authority and sacredness, while wavering between the two are a number of writers whose veneration for these books is tempered by some perplexity as to their exact standing, and among those we note St. Thomas Aquinas. Few are found to unequivocally acknowledge their canonicity. The prevailing attitude of Western medieval authors is substantially that of the Greek Fathers. The chief cause of this phenomenon in the West is to be sought in the influence, direct and indirect, of St. Jerome's depreciating Prologus (http://www.newadvent.org/cathen/03267a.htm)
But tell me, because I'd really like to know: who authorized the 16th century revised (or, as you might say, "reformed") canon used by your denomination? What person or group of persons by name? What year or even decade, by date? I'd like to look up these gentlemen and check out by what authority, or what qualifications, they claimed the right to determine the Scriptural canon.
Then you need to actually answer my questions of post 388 , and ask your question of the 1st c. souls who held to a canon of Scripture as authoritative before the Lord even was born, but thus to which the NT appealed to as its prophetic and doctrinal foundation. How could they even hold that John the baptizer was a prophet indeed, or the book of Isaiah if they needed an authoritative infallible church to tell them?