Scribe 2 of 𝓟 wrote “the waters of the river Sidon”. Somewhat later, Oliver Cowdery corrected this phrase to read “the waters of Sidon”, which is consistent with other usage in the text. There are seven other occurrences of “the waters of Sidon” but none of “the waters of the river Sidon”:
Here in Alma 2:34, we have the first occurrence in the text of “the waters of Sidon”, but earlier in this verse the text reads “on the west of the river Sidon”. This usage seems to have led scribe 2 to accidentally write “into the waters of the river Sidon”. The phrase “the river Sidon” is very frequent in the Book of Mormon text (occurring 27 times), yet it never occurs when referring to “the waters” of that river, probably because waters and river are of the same semantic class. It is doubtful, however, that Oliver Cowdery would have been aware of these systematic differences; he probably made this correction in 𝓟 because 𝓞 actually read without the river.
Summary: Accept in Alma 2:32 Oliver Cowdery’s correction in 𝓟 of scribe 2’s “the waters of the river Sidon” to “the waters of Sidon”; Oliver’s correction was most probably based on the reading of 𝓞 and is consistent with all other usage in the text.