As explained earlier under Mormon 9:31, there are instances of imperfection and imperfections in the earliest text. Besides the three cases in verse 31 and the one here in verse 33, there is one other occurrence, and that example is in the plural:
Here in Mormon 9:33, scribe 2 of 𝓟 initially wrote the plural imperfections, but Oliver Cowdery later corrected 𝓟 to the singular when he proofed 𝓟 against 𝓞. His correction agrees with the singular imperfection in the 1830 edition.
The 1837 edition replaced the none with no, the expected negative quantifier in current English. When none modifies a following noun, we find that the noun is always in the singular (assuming the noun allows for a choice between singular and plural). For instance, there are 11 occurrences of “none other ” in the Book of Mormon text, and in each case the following noun is in the singular, as in 2 Nephi 2:30: “and I have none other object”. In all these cases, however, the plural would sound odd in English. There are also two instances of none directly modifying other, and in those two cases the noun takes the singular other (not the plural others):
These two examples therefore support the singular imperfection in Mormon 9:33.
Here in Mormon 9:33, we have the only instance in the history of the text where none has ever been replaced by no, which suggests that the 1837 change from none to no may be a typo rather than the result of Joseph Smith’s editing (he did not mark the change in 𝓟). In any case, the critical text will restore the original none here in Mormon 9:33 as well as maintain the singular imperfection.
Summary: Maintain in Mormon 9:33 the original singular imperfection, the 1830 reading as well as the corrected reading in 𝓟; also restore in this passage the original none that preceded imperfection; the 1837 change of none to no may have been accidental; usage elsewhere in the text supports the singular noun form after none.