Complex sentence: Apostles John W. Taylor and Matthias F. Cowley were each released from the Quorum of the Twelve Apostles for "disharmony" with the church's position on plural marriage in 1906, and plural marriage continues to be grounds for excommunication from the church.
Split into simpler sentences: Apostles John W. Taylor and Matthias F. Cowley each resigned from the Quorum of the Twelve Apostles due to disagreement with the church's position on plural marriage. Plural marriage continues to be grounds for excommunication from the church.