Scribe 3 of 𝓞 originally wrote “many of home are pres[s]ing forward”. Quite obviously, the presenttense are is a mistake for were. Scribe 3 nearly always wrote ware for were. The are here is probably a scribal slip for his intended ware. Interestingly, he did correct the spelling home to whome by inserting (with weaker ink flow) a w in the margin right in front of the word home. Perhaps he also thought to correct the are to ware (by adding a w) but neglected to do so.
In any event, Oliver Cowdery emended the are to were when he copied the text from 𝓞 into 𝓟. Nephi’s entire description of his father’s dream is in the past tense (and without variation), so Oliver’s emendation is undoubtedly correct.
Summary: Scribe 3’s are in 1 Nephi 8:21 is an obvious scribal slip for ware ‘were’; Oliver Cowdery correctly emended the text to were.