Greetings in that Divine and Most Precious Name of Our Lord and Savior Jesus Christ!
If I recall, Eutyches himself was personally exonerated after he reformed his bungled confessions and affirmed the Niceo-Constantinople Creed, but those heretical teachings rightfully or wrongfully attributed to him were condemned both by the EOs and the OO several times over, but I am not sure which source exactly I read or heard this from.
By the way, Father Peter's article on Eutyches is very very enlightening about the sociopolitical context.
XXXI. ---- OF THE HOLY SEVERUS FROM THE LETTER TO SERGIUS THE PHYSICIAN AND SOPHIST. [515-8.]
But with regard to the reception of Eutyches that it was done in a canonical way, and that it casts no slur on the holy. Dioscorus, and on the synod which assembled with him at Ephesus, I addressed the arguments on this head to certain persons some time ago, and I also dealt completely with it as the truth demands; and I have thought it good and urgent to send a copy of these things to your learning. Not only the wretched man from Scythopolis 220, but many others besides before him and after him, employed the same blasphemous absurdities, not knowing what they are saying 221, but made empty-mindedness fulness of blasphemy against God. The holy synod which assembled at Ephesus with the saintly witness of the truth Dioscorus taught nothing new whatever with regard to the faith, but only effected the deprivation 222 of those who were infected with the Jewish poison of |93 Nestorius and cast them off: but Eutyches, who presented a petition and anathematized his heresy, on account of which he was accused, it accepted on the ground of the actual petition itself and on the ground of the minutes 223 that were written at Constantinople before Flavian, since it did not recognise the poison that was in his heart, and the disease hard to be discovered was in accordance with the human standard properly hidden from it; for the divine Scripture plainly teaches that 'man looks on the face, but God looks on the heart' 224. But what will anyone say about those who assembled at Chalcedon, who received Theodoret and Hiba, who not merely hid the foul heresy of Nestorius in the heart, but actually displayed it with open face. When the contents of the minutes' on account of which Hiba's deprivation 225 took place had been read, and his letter to Mari the Persian, which was full of many blasphemies (a copy of which I have also sent to you), the representatives of Leo, who had become prelate of the church of the Romans, pronounced him blameless, making the following declaration 226: «Pascasinus and Lucentius the reverend bishops and Boniface the presbyter representing |94 the apostolic throne 227 said by the mouth of Pascasinus, 'From the reading of the documents 228, and from the statement 229 of the reverend bishops we know that the reverend Hiba has been shown to be innocent. For, when his letter was read, we recognised that it is orthodox 230; and therefore our decision is that the episcopal rank also and the church from which he was wrongfully ejected in his absence be restored'» 231. And to these things the whole synod assented; and they promulgated the same decision. How then can those who defend those men dare to make the reception of Eutyches, which took place according to the canons, a charge against the holy Dioscorus and the synod which assembled with him?
XXXII. -------- OF THE SAME FROM THE LETTER TO THE ORTHODOX 232 BROTHERS IN THE CITY OF TYRE, WHICH IS SUR. [513-8.]
Since you have thought fit to ask me for what reason Eutyches is anathematized, the man of ill name 233 and impious, and how it is that he was received by Dioscorus of saintly memory, we say in a few words that he was |95received on presenting a document 234 which contained a right confession of faith and anathematized Mani and Valentine, and Apollinaris, and those who say that the flesh of our Lord and God Jesus Christ came down from heaven; to which he further added the words that follow (though those who assembled at Chalcedon interrupted the reading, when the things that were written at Ephesus in the transactions 235 concerning him were put in), that the things which they wished to impute to him were slanders 236. But the man of ill name seems again to have 'returned to his vomit' 237. And that 238.....
XXXIII. ---- OF THE HOLY SEVERUS, FROM THE LETTER TO NEON THE PRESBYTER AND ARCHIMANDRITE 239, ABOUT THE RECEPTION OF EUTYCHES. [513-8.]
And, in order not to extend the letter to a great length, from these declarations 240 it has been clearly made known that, as we said, in consequence of the document' and of the minutes 241 written in the royal city, and of the depositions 242 on behalf of Eutyches that are contained in them the holy synod |96 which then assembled in the city of the Ephesians gave a decision by which it declared this man innocent; and it can never be accused on account of the fact that after these things the same Eutyches ran back to the vomit 243 of his own evil opinion. For neither against the holy fathers did this bring a reproach, because many heretics consented to a temporary hypocrisy, and again returned to their impiety; since even with the 318 holy fathers Eusebius Pamphili both sat in concourse with them and was one of their number; and he contended with these on behalf of the madness of Arius, and armed himself against those who held the right opinions.
(And a little farther on.)
But in the synod at Chalcedon Dioscorus said this: «But, if Eutyches holds anything outside the doctrines of the church, he deserves not merely punishment, but even fire. But I concern myself for the catholic and apostolic faith, not for any man soever» 244. But that the saintly man of saintly memory acknowledged Emmanuel who is of the Father's nature in |97 the Godhead himself to have become also of our nature in the manhood, how do we need any other testimony, since the minutes 245 that were written in Constantinople before Flavian, and brought in again at Ephesus, plainly contain this expression, which was confessed by Eutyches, and confirmed by him, in that he asked that synod, «Do we all also agree to these things?» and they said, «We agree» 246?
Letters of Saint Severus
It seems that even with Severus, Eutyches was back and forth..