As discussed under 2 Nephi 22:2, there are a few instances in the original text where the perfect auxiliary was be rather than have. In older English, the be verb was used in this way with verbs of motion or change, as in the familiar phrase “the hour is come” (Mark 14:41) rather than “the hour hath come” (or in modern English, “the hour has come”). The same usage occurs with the verb become, as in Genesis 3:22: “behold the man is become as one of us”. For a complete discussion regarding this usage in the original text of the Book of Mormon, see under perfect in volume 3.
Summary: Maintain in Helaman 13:36 the archaic use of the perfect auxiliary be with the verb become (“and all things are become slippery”), the reading of the earliest textual sources (𝓟 and the 1830 edition, both firsthand copies of 𝓞).