Here scribe 2 of 𝓟 initially wrote the past participle conferred as a present participle, conferring (his spelling has only a single r). He immediately erased the incorrect -ing ending and overwrote it with the correct -ed ending. This error was undoubtedly influenced by the immediately preceding having. For similar examples of this kind of error, see the discussion under Mosiah 12:2.
Summary: Maintain in Mosiah 29:42 the past participial form conferred, the immediately corrected reading in 𝓟.