Why not? The Adam-God theory comes to my mind. Brigham Young believed in this doctrine and was later recanted by the church.
Excellent question. I think it's possible because prophets have their own views and revelations may change from time to time.
Prophets can believe whatever they please, they're not bound to believe certain things depending on which prophet from the past we're talking about. The Lord has the right to give revelation at any time and whatever He feels is needed for the Saints.
I am sure that the people in the Book of Mormon, who were lead astray were not aware their leaders were doing it, and maybe the leaders did not realize it either in some cases, but it happens, and it has happened.
Anyone who is an avid reader of the Book of Mormon, should know it foretells, along with the D & C, that the Gentile LDS Church will eventually slide into Apostasy; the Lord declared when wickedness has reach a certain level in the US and in the Church, he will commence the cleansing in his house first; this is also seen in the parables of the separation of the wheat and tares, separation of the sheep and goats, and the parable of the 10 Virgins; even in our Ward, it is taught and known, that the 10 Virgins are active spiritual members, so half will not hear his voice and not make it to the Saviors Wedding Party, and will be shut out.
The Lord says, my sheep hear my voice, and I know them; the sheep will most likely leave or be excommunicated and the main membership will not even know it.
When I joined the Church 40 years ago, we were taught to never follow any leader blindly, confirm everything against the Holy Ghost, and increasingly the Spirt has failed to confirm important things.
If you read and study, one should see that things started drifting as soon as Brother Joseph was killed, and the Church today is not what the Lord intended or wants.
It didd slowly creep into the Church, that the Prophet will never lead you astray, but what prophet, the only know I am sure of, is Joseph Smith. I was taught as well, when I joined the Church 40 years ago, we were told, always test against Scripture and the Holy Ghost, we told, never put your trust in the Arm of Flesh.
Bethouhumble, for the Prophet/President of the Church to be alarmed, one would have to assume he was aware and inspired. The last Prophet that I really could feel the Spirit with and the Holy Spirit testified to me, he was the one, was President Benson, somewhat with those that followed him, but I have never felt a confirmation from the Holy Ghost for our present President/Prophet.
Maybe you need to investigate the works of Denver Snuffer, but then maybe not, if you are not aware of what the Book of Mormon says.
D & C 112: