As noted under 1 Nephi 10:17, Joseph Smith removed 48 examples of the biblical phrase “it came to pass” in his editing for the 1837 edition. For this particular instance here in Mosiah 22:9–10, the apparent motivation was that the second instance of “it came to pass” was purely redundant since Gideon’s advice was precisely that—to gather their flocks together and to get the Lamanite guards drunk:
Such redundant uses of the “it came to pass” phrase have been generally removed from the text, although this kind of repetitive usage can be found in the Hebrew text for Genesis but not in the corresponding King James translation of it; for specific examples and discussion, see pages 35–37 of my article “The Original Language of the Book of Mormon: Upstate New York Dialects, King James English, or Hebrew?” Journal of Book of Mormon Studies 3 /1 (1994): 28–38. For a general discussion of this particular Hebraistic aspect of the original Book of Mormon text, see under come to pass in volume 3. The critical text will restore all these examples of what might be considered unnecessary repetition of the biblical phrase “it came to pass”.
In this particular instance of 1837 editing, Joseph Smith initially crossed out the original ampersand in the printer’s manuscript as well as the following it came to pass. But then he apparently decided that he needed a connecting and to follow the preceding sentence, so he supralinearly restored the and.
Summary: Restore the redundant use of “it came to pass” in Mosiah 22:10; such usage is characteristic of the original Book of Mormon text as well as the Hebrew text for Genesis (but not the corresponding King James English-language translation).