The final, official copy of the Constitution was copied by Jacob Shallus, a professional calligrapher, from the rough copy that had been already been approved (after months of debate) by the Constitutional Convention. At that point, the text was already finalized; so this corrected line must have been a scribal error by Shallus, not an active revision.

After he finished, [official scribe Jacob] Shallus had to deal with several mistakes that he had made during that rushed weekend of exacting labor. […] But he also used a penknife to scrape away an entire line of text near the bottom of page one, leaving behind a roughed-up band that now appears gray from grime.

https://www.archives.gov/publications/prologue/2012/fall/const-errors.html

So it would seem to have been a transcription error that was scraped off.