It's amazing John Eastman, constitutional lawyer, even has to write this article, because the 14th Amendment is explicitly clear - natural born US citizens can only be from US citizen parents, and permanent US residents who have been approved by the US government.
The 14th Amendment was ratified in 1868, making birthright citizenship illegal at that point.
Therefore, any child who had the status of US citizen mistakenly attached to them could have that designation corrected to the citizenship of their parents.