The original manuscript is not extant here for the first part of this sentence. In the printer’s manuscript, Oliver Cowdery initially wrote dissensions, but he later corrected this word to dissenters by crossing out the final sions and supralinearly inserting ters. The quill for this correction was sharper, which argues that this change was made later, probably when Oliver proofed 𝓟 against 𝓞. The lacuna in 𝓞 is large enough that we cannot tell for sure whether it read dissenters or dissensions, but usage elsewhere in the text argues strongly that it would have read dissenters since dissensions never “go forth” in the Book of Mormon but dissenters do:
In fact, the last example uses that same verb phrase, “to go forth”.
Summary: Maintain in Alma 63:14 the corrected reading in 𝓟: “there were some dissenters which had gone forth unto the Lamanites”.