"I would go to the actual census image and change it back to J. C."
That would really have no short-term effect other than to immediately list dueling alternates. Eventually it would become a permanent, bracketed and searchable fixture on the index page (unless some astute ACOM oversight were to intervene).
Nor would it address the real problem here...alternate info now replacing original document data in the ACOM attachment process.
I hope some ACOM rep will give us a clue as to just what is transpiring here. I'm fairly confident it was not purposeful.