The Community of Christ–formerly known as the Reformed Church of Jesus Christ of Latter-day Saints (RLDS)–is a schism of the Church of Jesus Christ of Latter-day Saints (LDS). They separated from the main body of the church after Joseph Smith's death, believing that the line of prophetic succession should follow Smith's bloodline.
Since then, they have made many fundamental changes to their doctrine, the most surprising change being that they now believe in the doctrine of the trinity.
Joseph Smith saw God the father and the Son standing side by side.
I saw two Personages, whose brightness and glory defy all description, standing above me in the air. One of them spake unto me, calling me by name and said, pointing to the other—This is My Beloved Son. Hear Him! (Joseph Smith History 1:17)
Joseph Smith clearly taught that God the Father, Jesus Christ, and the Holy Ghost were individual beings, and that both the Father and Christ had bodies of flesh and bone (see D&C 130:22).
To this day the Community of Christ identifies Joseph Smith as their founder. (see Community of Christ: History), and just prior to his martyrdom, Joseph Smith was quoted saying:
"I have always and in all congregations when I have preached on the subject of the Deity, it has been the plurality of Gods. It has been preached by the Elders for fifteen years." (Joseph Smith, June 16, 1844).
At what point did the RLDS abandon the most fundamental doctrine of the restoration and adopt the trinity?