For example the Eastern Church, and the Protestant churches are at odds with a fairly recent (1854) Catholic proclamation about a new Catholic doctrine called "the immaculate conception" which is generally regarded to be unscriptural.
Because of the Pope claiming to speak for God, such anomalies can't easily be corrected. It is one of the sticking points against the reunification of the Roman Church with the Eastern Church, after the schism of 1054.
That's not an accurate description of the extraordinary Papal magisterium at all. An ex cathedra dogmatic definition is not a "message from God". Technically, neither a dogmatic definition by the Pope nor one by an ecumenical council "have the force of Scripture". They are preserved from error -- a merely negative claim -- while Scripture is inspired, a higher claim of authority which means that Scripture says precisely what God wished to be said.
For example the Eastern Church, and the Protestant churches are at odds with a fairly recent (1854) Catholic proclamation about a new Catholic doctrine called "the immaculate conception" which is generally regarded to be unscriptural.
Who is this "generally" of whom you speak? The Orthodox and Protestants reject the Immaculate Conception, although for almost opposite reasons. So what?
Even at the first Council, the statement "it seemed good to the Holy Spirit and to us" does not make the claim that this is a God-mandated ruling here for all people at all places and times.
Not even the rarer-than-a-full-eclipse "infallible" statements are purportedly justified as, or presented as, a "personal message" from God to the Pope.