Here Oliver Cowdery initially started to write also. He almost finished writing the word when he aborted the final o, overwrote the so with w, and then continued inline with the ays. Thus his correction was immediate. Theoretically, either reading is possible, but always is definitely the correct reading here. The probable source for Oliver’s initial error was the occurrence of also in a nearly identical clause in the preceding verse: “yea and I also remember the captivity of my fathers” (Alma 29:11). For a similar example where always was accidentally replaced by also, an error that entered the printed text, see nearby under Alma 30:52.
Summary: Maintain in Alma 29:12 the immediately corrected reading in 𝓞: “yea I have always remembered the captivity of my fathers”.