Here the 1841 British edition omitted the subordinate conjunction that after “it came to pass”. The subsequent LDS edition (1849) restored the that. Both 𝓟 and the 1830 edition have the that, so most likely 𝓞 did too. The critical text will maintain the that here. For another example of the loss of the that after the phrase “come to pass”, see nearby under 3 Nephi 4:5.
Summary: Maintain in 3 Nephi 4:1 the that after “it came to pass”, the reading of the earliest text.