There are no similar words or phrases here that could have led Oliver Cowdery to visually skip this part of the text. Instead, his eye seems to have skipped down past an entire line of 𝓞 as he initially copied from 𝓞 into 𝓟. Later, probably while proofing 𝓟 against 𝓞, he discovered his error and supplied the text that he had originally omitted (the supralinear insertion is in heavier ink). Clearly, the passage would have read perfectly fine without the added text; thus there was no motivation to insert this line of text except that it was the reading of the original manuscript.
Summary: Accept the corrected reading in Mosiah 17:2 that seems to involve an entire line of 𝓞 that Oliver Cowdery initially skipped as he copied from 𝓞 into 𝓟.