The original text here in Alma 50:37 has four occurrences of that. The first and the last instances are the subordinate conjunction that, both of which refer to the initial “and it came to pass”. When Oliver Cowdery initially wrote the text down here in the original manuscript, he accidentally missed the repeated subordinate conjunction, but somewhat later (probably when he read back the text to Joseph Smith), he supralinearly inserted the that before Nephihah (the correcting that is written with somewhat heavier ink flow). The use of the repeated subordinate conjunction that is common in speech and unedited writing (as in “he said that after he returned from vacation next week that he would take up the matter”). In standard editing, the repeated that would be removed. The original text of the Book of Mormon has numerous instances of this colloquial usage; in fact, many instances of repeated that have been retained in the standard text. For some examples, see the discussion under 1 Nephi 10:2–3; for a complete list of examples, see under that in volume 3.
Here in Alma 50:37, we also see the tendency of Oliver Cowdery to replace the demonstrative that with the in the phrase “in that same year”, giving “in the same year”. In this case, he made the mistake as he copied from 𝓞 into 𝓟. Earlier in this chapter, Oliver made the same error in 𝓞 but immediately corrected it:
In that case, Oliver initially wrote the in 𝓞; then he immediately overwrote the e with an a and wrote the final t inline before continuing on with same year. We also saw this same tendency to replace that with the in the phrase “that same servant” in Alma 47:34 (see under that passage for other cases of this mix-up).
We also have one case of the relative pronoun that here in Alma 50:37: “in that same year that the people of Nephi had peace restored unto them”. In the original manuscript, Oliver Cowdery initially skipped this relative pronoun as he took down Joseph Smith’s dictation. His correction was immediate; after writing the the of the subject noun phrase “the people of Nephi”, he overwrote the e with an a and then wrote the t inline before continuing with the People (in other words, he made the same basic kind of correction as he did in Alma 50:15, mentioned just above in the previous paragraph).
Readers have difficulty processing the relative pronoun that in this passage since they tend to interpret it as a subordinate conjunction—in other words, they tend to initially interpret this sentence as if it read “and it came to pass ... that the people of Nephi had peace restored unto them”. Of course, this interpretation is incorrect since the previous verse (Alma 50:36) has already said as much. It is possible here in verse 37 that the original text actually read when instead of that and that when was accidentally replaced by that as Joseph Smith dictated the text to Oliver Cowdery. One could argue that the three other that ’s in this passage led to the introduction of a fourth one. For an independent example where the relative pronoun when was replaced by that (although in that instance the replacement occurred as Oliver copied the text from 𝓞 to 𝓟), see under Alma 40:5. As discussed under that passage, either that or when is possible. And even if that is the correct relative pronoun here in Alma 50:37, one could emend the standard text by replacing the that with when, not as an instance of conjecture, but simply as a help with the reading of the text:
Of course, the critical text will keep all four of the original that ’s in this passage.
Summary: Restore in Alma 50:37 the original demonstrative that in the phrase “in that same year”; the other instances of that in this passage will also be maintained, including a repetition of the subordinate conjunction that and one instance of the relative pronoun that.