There is actually no official list of Ecumenical Councils in the Catholic Communion. This often comes as a surprise to modern people because we’re used to hearing about a set number, but that number was devised by historians based on their own criteria and didn’t become widely accepted until recent centuries. To this day there is no Catholic-wide “list” of Ecumenical Councils on an official level, despite what you might read in articles and books.
That being the case, the Melkite Church (and other Churches from the Eastern Orthodox tradition) keeps their own “official list”, which was established at Seven. This doesn’t mean that there is a rejection of the decisions of what are called the “Western Councils” (a term that Popes a recently as Pope Pius XII have used), just that they aren’t officially commemorated as Ecumenical Councils. They are true, correct, and orthodox, and reflect the Catholic Faith (albeit the latter ones are often exclusively in a Latin manner, until Vatican II where the Eastern Churches had significant (name removed by moderator)ut in shaping the Council).
One thing to keep in mind is that the Melkite Calendar has actual Feast Days for the various Councils, something the Latin Church doesn’t do. Since there is no “Official Catholic List”, and the Melkite Church accepts the orthodoxy of the teachings of the Western Councils, there’s no problem with saying there have been Seven Ecumenical Councils, though that statement might be confusing to those who don’t know about the Catholic Church’s lack of an official list.
Peace and God bless!
From what I have read, the Melkite Patriarch was forced to sign the document.