"Bethabara" is the place where one crossed a stream that fed into the river Jordan in order to enter Judea. The place is also known as "Bethany" in the gospels. Matthew and Mark were simply not inspired to be as precise and John.
We use generalizations without difficulty. If I ask where you were born, would you report the state, city, street address, floor and room number, naming the hospital you were born; or, simply name the city of your birth? Or at least the state. Are we inconsistent if we withhold information?
Consulting a map, one finds no contradiction.