Isaiah 11:3 (King James Bible) and shall make him of quick understanding in the fear of the LORD and he shall not judge after the sight of his eyes
In this passage, as Oliver Cowdery copied from 𝓞 into 𝓟, he initially wrote “and he shall not make him of quick understanding”, undoubtedly because the following clause read “and he shall not judge after the sight of his eyes”. Oliver immediately caught his error and crossed out the extra he and the not (there is no change in the level of ink flow for the crossouts). The corrected text agrees with the King James reading and was undoubtedly the reading in 𝓞.
Summary: Maintain in 2 Nephi 21:3 the corrected reading in 𝓟 (“and shall make him of quick understanding”), which is also the King James reading.