Well, I have known at least two Orthodox Priests who have converted to the Catholic Faith and their “Holy Orders” were automatically transferred as well.
It is also my understanding that if a MARRIED Orthodox or Lutheran or Episcopal Priest converts to the Catholic faith that they can also remain married and still be a Catholic Priest.
That’s because they were no longer in schism. I said their sacraments were valid, but illegitimate/illicit due to schism.
Of course, with Vatican II maybe that changed too. Nothing surprises me anymore.