The Gemara brings two Girsa'os as to whether Rav Sheshes said "Tani Isi" or "Isi Tani". Rashi explains that difference between is whether it was a statement or a wonderment.
If there would be any difference between the two versions, I would see the point in preserving the different versions. But if they mean exactly the same thing, is it indeed so common to pass down different versions of a statement of an Amora, if both versions mean the same thing in the final analysis?
And, is there another interpretation of these words in the Rishonim and Acharonim?
Q. Reese, Atlanta, Georgia
I didn't find a different explanation in the Rishonim. However, anytime the Gemara quotes two different versions of an expression or statement, there is always some kind of lasting difference between the two versions, though it might not always be apparent.
For example, in the second version where Rav Sheshes is showing astonishment at contradicting a Beraisa quoted by Isi, Rav Sheshes is doing many things. One is that he is endorsing Isi as a source beyond reproof. The Amoraim will often reject a Berasia by saying that not just anyone can reliably quote a Beraisa (besides Rav Chiya), and they will reject the fact that there is such a Beraisa.
Rav Sheshes' second statement is a general endorsement that any Beraisa quoted by Isi is correct, while his first statement does not show anything more than the fact that he believed this Beraisa was correct. Though this does not directly affect the Gemara at hand, it imparts important knowledge which can help us in other areas of the Gemara.
All the best,