Here in the original manuscript, Oliver Cowdery wrote “in the debths of humility” (in the manuscripts Oliver consistently spelled the p in depth with a b, thus debth). However, for the word following debths (namely, of ), Oliver started to write a different letter, which he erased, and then he overwrote the erasure with the o of of. When he erased that unidentifiable letter, he accidentally smeared the final s of debths, which made the word look like the singular debth. The result was that he copied this word into 𝓟 in the singular, ending up with “in the debth of humility”. The printed editions have maintained the singular depth here.
Elsewhere in the text, for the phrase “the depth(s) of humility” we have only the plural depths:
𝓞 is not extant for any of these five other occurrences, although for the last one both the 1830 edition and 𝓟 are firsthand copies of 𝓞 (no longer extant for 3 Nephi 12), and both these sources have the plural. Given this support from all other examples in the text, it is clear that the original reading in 𝓞 for Alma 62:41, the plural depths, should be restored. (For additional discussion of the variation between depth and depths, see under 1 Nephi 8:32.)
Summary: Restore in Alma 62:41 the plural depths, which is what Oliver initially wrote in the original manuscript before he accidentally erased the plural s while trying to write the following word of; the Book of Mormon text consistently reads depths in the phrase “the depth(s) of humility”.