Yes, you heard it right.
Because of a quick in C++, the code that enforces the halvings did not work as intended.
After the last halving, the cycle of halvings would have restarted resulting in more than 21M bitcoins.
We do think this was not Satoshis original intent and in 2014 this was fixed with BIP42.
https://github.com/bitcoin/bips/blob/master/bip-0042.mediawiki
Funny enough the BIP was released on the 1st of April and its definitely the most jokish BIP ever written.