If an Orthodox priest or bishop were to come home to Rome, he would not be re-ordained or re-consecrated. Nonetheless, prior to his coming to Rome, he would not be Catholic.Similarly, those whose marriages he witnessed while he was Orthodox would not now need to be remarried, etc.
patent +AMDG
What if someone married by an SSPX priest left the SSPX and became Roman Catholic; would they have to be remarried?