So glad you have solved the mystery. Mistranscribing banns as marriages is a well known gaffe. The gap between third reading and marriage is, strictly speaking, too long as banns are supposed to expire after three months. But the dual parish is correct. Banns have to be called in the parish of residence of both parties (plus the parish where the marriage is to take place if it is in neither of the two), though it was very, very common for one party to claim residence in their intended's parish to save cost and hassle.

Best wishes

Caroline