Were not many of the early Fathers accused of heresy on specific issues? To what could this have been attributed if not to private interpretation?
None of the Fathers were accused of heresy for their theologoumenna (hypotheses). Those who were anathematized are not the Fathers of the Church (i.e. Origen, Montanus, etc.) because they professed as truth their heresy.
St. Gregory of Nyssa, one of the Cappadocian Fathers and a disciple of Origen, proposed—no doubt under Origen's Gnostic influence—universal salvation. Unlike his mentor, he later recanted this teaching and accepted the orthodox view that not everyone will be saved because of unrepetance of some.
Blessed Augustine of Hippo, likewise reached a point of "no return" with his teaching and recanted many of his postulates in a somewhat lesser known work of his (one of his last) titled "Retractions." St. Augustine realized that the turth of the Orthodox Faith is contained in the Catholic Church and he, in the end, derferred to the Church.
The Church always accepts those who have strayed into heresy as long as they recant their heretical teaching, so there is hope for all Protestants. :)
OK, this I didn't know (although I found quite a few websites that called Origen a Father). In any event, as I indicated to Diva, I was specifically thinking of Origen, and to some extent Augustine. New Advent appears to back you up:
Great bishops and saints like Dionysius of Alexandria, Gregory Thaumaturgus of Pontus, Firmilian of Cappadocia, and Alexander of Jerusalem were proud to be disciples of the priest Origen. The bishop Cyprian called daily for the works of the priest Tertullian with the words "Give me the master". The Patriarch Athanasius refers for the ancient use of the word homoousios, not merely to the two Dionysii, but to the priest Theognostus. Yet these priest-teachers are not yet called Fathers, and the greatest among them, Tertullian, Clement, Origen, Hippolytus, Novatian, Lucian, happen to be tinged with heresy; two became antipopes; one is the father of Arianism; another was condemned by a general council. In each case we might apply the words used by St. Hilary of Tertullian: "Sequenti errore detraxit scriptis probabilibus auctoritatem" (Comm. in Matt., v, 1, cited by Vincent of Lérins, 2.4). (emphasis added)
While this seems to say that they were not technically Fathers, I still find it interesting how much influence they DID have over actual Fathers, even though they were "tinged with heresy". :)