yep, 2 digits year code mistake.
it happens in other countries too. saw a case of granma born in 1898 in the austro-hungarian empire.
her personal code ( kind of like SSN) matched the one of a 2 year old at the time.
what followed was a match between various institutions of "who-does-what". finally somebody stepped in and said "there is already a rule for born before 1900. use it!"