Daf Yomi Ketubot: Al Yedei Chuppa veKiddushin - What Is A Post-Talmudic Nusach Doing In Our Gemara?

Here is an interesting case of girsology and possible post-Talmudic addition. The gemara in Ketubot 7b records the nusach of the blessing of betrothal:

ברכת האירוסין מאי מברך רבין בר רב אדא ורבה בר רב אדא תרוייהו משמיה דרב יהודה אמרי בא"י אמ"ה אשר קדשנו במצותיו וצונו על העריות ואסר לנו את הארוסות והתיר לנו את הנשואות על ידי חופה וקדושין

רב אחא בריה דרבא מסיים בה משמיה דרב יהודה בא"י מקדש ישראל על ידי חופה וקדושין
מאן דלא חתים מידי דהוה אברכת פירות ואברכת מצות ומאן דחתים מידי דהוה אקידושא

[As to] the benediction of betrothal — what does one say? — Rabin b. R. Adda and Rabbah son of R. Adda both said in the name of Rab Judah: Blessed art Thou, O Lord our God, King of the Universe, who has sanctified us by his commandments and has commanded us concerning the forbidden relations and has forbidden unto us the betrothed and has allowed unto us the wedded through [the marriage] canopy and sanctification. R. Aha 'the son of Raba, concludes it in the name of Rab Judah, [with the words]: Blessed art Thou, O Lord, who sanctifies Israel through canopy and sanctification. He who does not seal [holds that] it is analogous to the blessing over fruits and to the benediction [said on performing] religious commandments. And he who seals [holds that] it is analogous to the kiddush

Of slight issue is the ending of the blessing -- בא"י מקדש ישראל על ידי חופה וקדושין -- Blessed art Thou, O Lord, who sanctifies Israel through canopy and sanctification.

In the Rif, we do not have this full ending. Instead, we have בא"י מקדש ישראל -- Blessed art Thou, O Lord, who sanctifies Israel. And the same from Rav Achai Gaon. And so with the Rosh:

אשר קדשנו במצותיו וצונו על העריות ואסר לנו את הארוסות והתיר לנו את הנשואות על ידי חופה וקידושין ברוך מקדש ישראל וכו' ונהגו האידנא מקדש ישראל על ידי חופה וקידושין.

Thus, he makes it clear that the nusach of the blessing did not include על ידי חופה וקדושין, for that is the nusach that he had then. The "etc." is presumably the continuation of the gemara, as the Rif would continue. The obvious difference between the blessing as formulated by the gemara and as practiced in the time of the Rosh would seem to be the time division between betrothal and nuptials, of a year. Since there is no chuppa present, some explain, it would be odd to include it in the closing. Once they are placed together, with the betrothal under the bridal canopy, it is more fitting.

But if this is so, what is this girsa of the blessing doing in our gemara? Is this not a post-Talmudic nusach? This might be another example to late editing, where someone filled in on the margins the ending of the blessing as practiced later, and it thus entered into our Talmudic manuscripts.

Might be find another answer? I would propose the following: The closing we have in our girsa makes sense, since it echoes the text of the body with its Al Yedei Chuppa veKiddushin. Sure, Rosh and Rif and Rav Achai Gaon had this nusach, but there was a parallel nusach of which they were unaware. This early nusach formed the basis of the nusach that the Rosh witnessed in his day. Yet, there was a distinction that the Rif witnessed between his own Talmudic text and the nusach of the blessing in his day. His assumption was that, rather than being a girsological difference, somehow the nusach had changed from the time of the gemara, such that he would label it haIdna.