That information is incorrect. It is a fantasy explanation though up by Anglican and Latin liturgists who had no other explanation for the "missing" explicit institution narrative. It was never there. This is supported by the fact that the liturgy of the Apostolic Constitutions does not have one, nor does the Maronite/Syrian Anaphora of Peter III (Sharar).
The institution narrative is implicit, at least that is how the Catholic Church deems it.
"We too, my Lord, your feeble, unworthy, and miserable servants who are gathered in your name and stand before you at this hour, and have received by tradition the example which is from you, while rejoicing, glorifying, exalting, and commemorating, perform this great, fearful, holy, life-giving, and divine Mystery of the passion, death, burial, and resurrection of our Lord and Savior, Jesus Christ. And may there come, O my Lord, your Holy Spirit, and may he rest upon this oblation of your servants. May he bless it and hallow it, and may it be for us, O my Lord, for the pardon of debts, the forgiveness of sins, the great hope of resurrection from the dead, and for new life in the kingdom of heaven with all who have been well-pleasing before you. And for all this great and marvelous dispensation towards us we will give thanks to you and praise you without ceasing in your church, which is saved by the precious blood of your Christ - with unclosed mouth and open face, (2) while lifting up praise, honor, confession, and worship to your living, holy, and life-giving name, now, always, and for ever and ever. Amen"(Anaphora of Mar Addai and Mar Mari).
On the otherhand, the Roman Canon has an implicit epiclesis, but not an explicit descending Epiclesis, the Byzantine Churches use. The Roman Canon uses an implicit ascending Epiclesis.
"Almighty God, we pray that your angel may take this sacrifice to your altar in heaven. Then, as we receive from this altar the sacred body and blood of your Son, let us be filled with every grace and blessing. Through Christ our Lord. Amen" (Roman Canon).
St. Nicholas Cabasilas recognized this and for the first thousand years no Eastern Church had a probelm witht the Roman Canon. In fact some Slavs translated it and used it on the Feast of SS. Peter and Paul, manuscripts were found on Mt. Athos attesting this. It is only later Byzantine chauvinism that caused some to say the Roman epiclesis was faulty and caused the Western Rite Orthodox to insert a Byzantine Epiclesis into the Roman Canon.
Fr. Deacon Lance