One of these is not like the other. The home Synod of Constantinople in 448 condemned Eutyches as a heretic. The issues involved were directly relevant to subsequent councils at Chalcedon and beyond.
Eutyches was not a theologian of any standing. He was a monk who held some standing in the monastic circles around Constantinople, having directed more than 300 monks over thirty years. He was a friend of Cyril, and an indefatigable supporter of the Alexandrine cause at the capitol. He had direct access to the emperor’s court.