@Doswin: the same havarah is also used by some chassidim, specifically in Dushinsky it is used also. “avoiseini” instead of “avoisaini”, as an example.
Many Hungarians say it like that. The “ai” is a Polish thing though nowadays it seems more common, since in general it seems many people move towards either 1 Litvishe havarah or 1 chassidishe with seemingly no variations and nothing in between. I don’t think it was historically like that.