Is the פְּנִיאֵל of BeReishis 32:31 the same as the פְּנוּאֵל of 32:32? If so, why the change in term used to refer to it? If not, is there a story behind the two places with such similar names?
It always seemed to me from reading the pesukim (and it seems Or HaChayim understands it this way as well) that the name of the place was Penuel and only Yaakov called it Peniel, presumably punning off the existing name of the place. Note that the location is mentioned many other times in Tanach and always as Penuel (Shoftim 8:8,9,17 Melachim 1:12:25 and I'd even include Divrei Hayamim 1:4:4).