The fact that every Published Vulgate from 405 onwards had this list of books? Or did that just happen at random?
If you paid much attention, you’d see that’s already been answered a few times on this thread.
Why you continue to post polemics that have been refuted ? however, there were various and variant copies of the Vulgate, while containing is not necessarily the same as being canonical.
At the end of the fourth century Pope Damasus commissioned Jerome, the most learned biblical scholar of his day, to prepare a standard Latin version of the Scriptures (the Latin Vulgate). In the Old Testament Jerome followed the Hebrew canon and by means of prefaces called the reader's attention to the separate category of the apocryphal books. Subsequent copyists of the Latin Bible, however, were not always careful to transmit Jerome's prefaces, and during the medieval period the Western Church generally regarded these books as part of the holy Scriptures. Introductory material to the appendix of the Vulgata Clementina , text in Latin
The 8th cent. Vulgate Codex Amiatinus contains the "Prologus Galeatus" of Jerome to the Books of the Kings and other prefaces (http://www.newadvent.org/cathen/04081a.htm; http://www.bible-researcher.com/jerome.html), which reminds us of the distinction between Scripture and the apocryphal books
Vulgate manuscripts included prologues that clearly identified certain books of the Vulgate Old Testament as apocryphal or non-canonical (Prologues of Saint Jerome , Latin text )
"...other Vulgate manuscripts included prologues that clearly identified certain books of the Vulgate Old Testament as apocryphal or non-canonical" - http://www.thelatinlibrary.com/bible/prologi.shtml
The Vulgate is understood to be a compound text that is not entirely the work of Jerome, (Grammar of the Vulgate, W.E. Plater and H.J. White, Oxford at the Clarendon Press, 1926)
One curious feature of many manuscripts of the Latin Vulgate is the inclusion of the apocryphal Epistola ad Laodicenses. - http://www.bible-researcher.com/laodiceans.html
In several ancient Latin manuscripts the spurious Epistle to the Laodiceans is found among the canonical letters, and, in a few instances, the apocryphal III Corinthians. - http://www.newadvent.org/cathen/03274a.htm
Moreover, while Trent did establish the Vulgate as the official Bible for that time, it did not specify which edition, nor elevate it above the original language manuscripts (though some disagree). The lack of uniformity among Vulgate editions and problems with that translation resulted in the embarrassing Sistine Vulgate . (Nor is the Douay-Challoner version a pure translation of the Vulgate.)
Correction of its many errors resulted in the first edition of the Clementine Vulgate (official version till 1979) which was presented as a Sixtine edition (with a preface in which Bellarmine charitably attributed the problem of the previous version to being that of copyist errors, rather than being the fault of Sixtus). In 1592, Pope Clement VIII published this revised edition of the Vulgate, referred to as the Sixto-Clementine Vulgate. He moved three books, 3 and 4 Esdras and the Prayer of Manasses (commonly found in medieval MSS of the Vulgate, immediately after 2Chronicles, and not found in the canon of the Council of Trent) from the Old Testament into an appendix "lest they utterly perish" (ne prorsus interirent). (http://sacredbible.org/vulgate1861/scans/817-Apocrypha.jpg)
Also of interest,
In the spring of 1907 the public press announced that Pius X had determined to begin preparations for a critical revision of the Latin Bible... In spite of the care which during forty years had been bestowed upon the text of the present authentic edition issued by Clement VIII, in 1592, it had been recognized from the first that the text would have to be revised some day, and that in some ways this Clementine revision was inferior to the Sixtine version of 1590, which it had hastily superseded. Catholic Encyclopedia>Revision of Vulgate; http://www.newadvent.org/cathen/15515b.htm
There is also no known 1st century LXX manuscripts with the apocrypha, and what we do have varies much and evidences to be of Christian compilation.