No they don't. Ecumenical councils DO NOT "trump" earlier councils or EX CATHEDRA pronouncements where they teach dogmatically. You suffer from the error of conilarism---the notion that an ecumenical council is the supreme law of the Church. This especially ironic with you insofar as the most concise teaching on the immutability of dogma comes from a ...wait for it....dogmatic council {DEI FILIUS, Vatican I}. BTW, it is your argument that is "fifty years old"; mine is 1900 years in the making.