Your comment: “According to Duns Scotus, transubstantiation was not an article of faith before the thirteenth century.”
That is not correct. The Catholic Church has often after time has documented the teachings and reaffirmed them.
The Apostles believed and taught the Real Presence of Jesus and is contained in the Bible:
1st Corinthians, 11:23-26. “For I received from the Lord what I shall deliver to you.”
23* For I received from the Lord what I also handed on to you,k that the Lord Jesus, on the night he was handed over, took bread, 24and, after he had given thanks, broke it and said, “This is my body that is for you. Do this in remembrance of me.” 25In the same way also the cup, after supper, saying, “This cup is the new covenant in my blood. Do this, as often as you drink it, in remembrance of me.”l 26For as often as you eat this bread and drink the cup, you proclaim the death of the Lord until he comes.
27Therefore whoever eats the bread or drinks the cup of the Lord unworthily will have to answer for the body and blood of the Lord.
If you want to argue with a doctor of your church, that’s fine by me. If it was accepted and settled as far back as the apostles, then why did the Lateran Council take it up?