I count four times where Rav Pappa notes differing opinions on how to conclude a bracha and rules to say both of them. In three of these cases, he uses a conjunctive ו to connect them, but not the fourth. (In all the quotations below, I've cut out the portions which are not relevant to Rav Pappa's statements in each.)
מאי מברך ברוך זוכר הברית במתניתא תנא ר' ישמעאל בנו של ר' יוחנן בן ברוקא אומר נאמן בבריתו וקיים במאמרו א"ר פפא הלכך נימרינהו לתרוייהו ברוך זוכר הברית ונאמן בבריתו וקיים במאמרו
What does one bless [on a rainbow]? "Blessed is He Who remembers the covanent [with Noach]." In a Braisa it was taught: "R' Yishmael the son of R' Yochanan ben Beroka says, 'Trustworthy in His covanent and upholds His word.'" Rav Pappa said, "Therefore, let's say both of them: 'Blessed is He Who remembers His covanent and is trustworthy in His covanent and upholds His word.'"
מַאי מְבָרְכִין [...] וְרַבִּי יוֹחָנָן מְסַיֵּים בַּהּ הָכִי אִילּוּ פִּינוּ מָלֵא שִׁירָה כַּיָּם וְכוּ' אֵין אֲנַחְנוּ מַסְפִּיקִין לְהוֹדוֹת לְךָ ה' אֱלֹהֵינוּ עַד תִּשְׁתַּחֲוֶה בָּרוּךְ אַתָּה ה' רוֹב הַהוֹדָאוֹת רוֹב הַהוֹדָאוֹת וְלָא כׇּל הַהוֹדָאוֹת אָמַר רָבָא אֵימָא הָאֵל הַהוֹדָאוֹת אָמַר רַב פָּפָּא הִלְכָּךְ נֵימְרִינְהוּ לְתַרְוַיְיהוּ רוֹב הַהוֹדָאוֹת וְהָאֵל הַהוֹדָאוֹת
What does one bless [on abundant rain]? [...] R' Yochanan would conclude it thus, "If our mouths were full of song like the sea...we would not be able to sufficiently thank You, Hashem, our G-d," until "...bow. Blessed are You, Hashem, abundant thanksgivings." Abundant thanksgivings, and not all thanksgivings?! Rava said, "Say, 'The G-d of thanksgivings.'" Rav Pappa said, "Therefore, let's say both of them: 'Abundant thanksgivings, and the G-d of thanksgivings.'"
מַאי חָתֵים [...] אָמַר שְׁמוּאֵל [...] רוֹפֵא כׇל בָּשָׂר רַב שֵׁשֶׁת אָמַר מַפְלִיא לַעֲשׂוֹת אָמַר רַב פָּפָּא הִלְכָּךְ נֵמְרִינְהוּ לְתַרְוַיְיהוּ רוֹפֵא כׇל בָּשָׂר וּמַפְלִיא לַעֲשׂוֹת
How should one conclude [Asher Yatzar]? [...] Shmuel said, "[...] Healer of all flesh." Rav Sheshes said, "Who does wondrous deeds." Rav Pappa said, "Therefore, let's say both of them: 'Healer of all flesh, and Who does wondrous deeds.'"
In all of these three cases, Rav Pappa splices the two versions with a conjunctive. Yet in the fourth example, in Megillah 21b, he does not put anything in between the two conclusions.
לאחריה מאי מברך [...] ברוך אתה ה' הנפרע לישראל מכל צריהם רבא אמר האל המושיע אמר רב פפא הלכך נימרינהו לתרוייהו ברוך אתה ה' הנפרע לישראל מכל צריהם האל המושיע
After [the Megillah], what does one bless? "[...] Blessed are You, Hashem, Who exacts punishment for Yisrael from all of their enemies." Rava said, "The G-d Who saves." Rav Pappa said, "Therefore, let's say both of them: 'Blessed are You, Hashem, Who exacts punishment for Yisrael from all of their enemies, the G-d Who saves.'"
Why is there this discrepancy?
(I'd be interested to see if anyone indeed alters these texts, but I'd prefer answers which preserve the text as we have it.)
