““Natural Born Citizen” has ALWAYS meant “Citizen at the Moment of Birth”
WRONG! The person whose father was born in Canada to two U.S. citizens, is a “citizen at birth”. FACT
Are you saying he would be eligible to be president of the United States (a Natural Born Citizen) having been born in a foreign country?
That IS what you are saying and it is RIDICULOUS!
Your example depends on the age of the parents and the year of said birth.
Congress has changed the citizenship rules a few times.