Initially in the original manuscript, Oliver Cowdery wrote “they would stir up the Lamanites to anger against them and come down to battle against them”. Later Oliver supplied the phrase “cause them to”, supralinearly inserting it with somewhat heavier ink flow. Oliver’s correction here probably occurred when he read back the text to Joseph Smith.
Summary: Accept in Alma 46:30 the corrected reading in 𝓞: “and cause them to come down to battle against them”.