In Bamidbar (26:23):
בְּנֵ֤י יִשָּׂשכָר֙ לְמִשְׁפְּחֹתָ֔ם תּוֹלָ֕ע מִשְׁפַּ֖חַת הַתּוֹלָעִ֑י לְפֻוָ֕ה מִשְׁפַּ֖חַת הַפּוּנִֽי׃
Descendants of Issachar by their clans: [Of] Tola, the clan of the Tolaites; of Puvah, the clan of the Punites;
The Puvah family is brought as a son of yisachar, but when it says the clan name it says “clan of Punites”, not “clan of Puvites”! Why?
(Note: Onkelos has both Puni and Puvah, according to the Chumash in front of me)