I suppose it’s the one about the source of sacerdotal unity? That was my first guess.
(Aye, that and the related one about where error cannot enter. I hesitate to cite it because I do think it’s easy for Catholics to take out of context. Actually, the nature of the dispute between St. Cyprian and Pope St. Stephen to me is a crystal-clear indicator of the truth of the High Petrine interpretation: St. Cyprian insisted on his episcopal prerogative because he saw the issue at hand to be, by definition, one belonging to a bishop’s proper jurisdiction, and St. Stephen presumed the right to dispute this, because he saw it as an issue of inherently universal relevance.)
Certainly the definition of primacy is not the same between the two communions.
For example, the primate of the RC church in the USA is the Archbishop of Baltimore (and the primate of Italy is the Archbishop of Rome). What does that mean in practice? Almost nothing. Most RC don’t even know the Archbishop of Baltimore has primacy in the USA. The position has so atrophied under the increasingly powerful papacy in recent centuries it has even lost it’s symbolic value.
Today, among RC when ‘primacy’ is mentioned it is automatically assumed to refer to papal prerogatives. People have almost all nearly completely forgotten what it used to mean in their own church.
The fact is, in the early church primacy functioned at many levels.
We can fix that. It may take a long time, but as long as our Lord hasn’t returned yet, we’ll be working on it.
About the positions that Eastern Catholics are taking that are not consistent with Roman Catholic teaching.
While I really can’t comment responsibly since I wasn’t there and don’t know specifics, I’ll say something nonetheless.

I would not at all be surprised if he doesn’t understand Catholic teaching.
In his defense, I
have heard some eastern Catholics take positions that aren’t consistent with Catholic teaching: for instance, an old thread on the ByzCath forums once held a “Melkite FAQ” by a Melkite Catholic on what Melkites believe. He claimed -
without further clarification - that Melkites don’t believe in papal infallibility.
If that’s the sort of thing you and your OCA priest friend were discussing, then I agree with you. More often, however, what I hear is unjustified suspicion - from, ironically, Catholics as well as Orthodox - that the laudably and justly nuanced explorations and expressions of Catholic teaching from the perspective of eastern theology and spirituality are actually inconsistent with Magisterial teaching; this most often happens in the context of papal supremacy and universal papal authority. All the while those who harbor such suspicions absurdly ignore the self-evident fact of Catholic theology’s extraordinary capacity for flexibility and nuance.
He also told me that Eastern Catholics can never be Orthodox in communion with Rome. I was offended and hurt at first, but after much contemplation I discovered that he is right about that matter.
I’m not surprised he said that. It only makes sense for a devoted Orthodox priest.
But to the Orthodox, orthodoxy is believing in the faith of our Church Fathers. The beliefs and practices of the First Millennium.
This is one of the reasons I find the Catholic hermeneutic of Tradition more compelling: while revelation ended with the death of the last Apostle, is “development of doctrine” in any sense permissible?
To me, the Orthodox often seem to want to say “no,” and yet they (rightly!) value the Church Fathers and first seven Ecumenical Councils as necessary bulwarks and foundations of the Orthodox Faith.
Well, if - as we all agree - public divine revelation ended with the death of the last Apostle, then why is theological development so easily permissible in the first millennium but so ideologically anathematized in the second?
**To be fair, I
don’t think this is a flaw in the faith of our Orthodox brothers and sisters; I think it’s a flaw in contemporary EO
apologetics. **Their often suspicious response to Latin development leaves their own perspective on Tradition deeply incoherent.
We look at the ancient Western Church and say “that’s our faith”.
And then we Catholics experience puzzlement in light of figures like St. Leo the Great, concerning whose actions you guys - well, perhaps not the OO, but certainly the EO - let slide the very straws that apparently broke the camel’s back in the eleventh century.
And we ask why it was okay for us to get away with certain things then, but not now…
It is the greatest roadblock to unity. I was one of those that started to believe that unity is around the corner. But after understanding the Orthodox side and reading Pastor Aeternus, I don’t believe that we will be reunited with any of the Apostolic Churches with that document in effect as is.
See, I do
not believe that unity is right around the corner, for practical reasons, despite the fact that I believe Pastor Aeternus is not Absolutist…
I find the Catholic reliance on miracles disturbing.
In what way, Nine_Two? I don’t think we rely on miracles… I don’t, anyway. Well, I suppose I rely on one: the Resurrection of our Lord…