We begin to learn that there was religious apostasy among the people as well as political differences. We do not learn where those religious differences came from, but if we assume that the Jaredites arrived in the New World along the Gulf Coast of Mexico (which is a plausible assumption), they would have discovered people already there, just as the later people of Lehi must have discovered when they landed in a different location, on a different coast. Those people were forming a culture that is now known as Olmec, which is a name given to a general set of artistic and other physical remains that have similarities in region and time. The religion of the people we call Olmec would have been different from that of the Jaredites. It is quite likely that the early religious difficulties arose from the conflicts with the previously dominant religion of the region.
The situation is widespread enough that the people reject the prophets, and king Shule had to step in to make peace. He did, and kept peace through the remainder of his days.
This is not the end of a chapter in the 1830 edition of the Book of Mormon.