The Mishna says:
כָּל קָרְבְּנוֹת הַצִּבּוּר וְהַיָּחִיד בָּאִים מִן הָאָרֶץ וּמִחוּצָה לָאָרֶץ ...
All public and private offerings [of grain -IM] can be brought from the Land [of Israel] or outside the Land ...
The Mishna goes on to list particular sources for the "best" grain, which happen to be in the Land of Israel, but then clarifies:
כָּל הָאֲרָצוֹת הָיוּ כְשֵׁרוֹת, אֶלָּא מִכָּאן הָיוּ מְבִיאִים
[The grain of] all the lands were suitable, but this is where they would bring from [in practice].
my translation here and below
In his gloss on this sentence, R' Ovadia makes a significant insertion:
כל הארצות. של ארץ ישראל היו כשרות, אלא שמכאן היו מביאים
[The grain of] all the lands of the Land of Israel were suitable, but this is where they would bring from [in practice].
Why does R' Ovadia apparently go out of his way to make the last part of the mishna contradict the first part? Reading the text of the mishna, it would seem that the last sentence, with "all the lands," is reiterating "the Land and outside the Land" from the first sentence, not contradicting it.
Also, what does it mean, according to R' Ovadia, that the last part contradicts the first part? Does this indicate a dispute in the Mishna, an evolution of Halacha, or something else?