IMHO, the person who spent those coins might not even know about the puzzle at all
That's an impossible scenario, particularly if they are not the original owner of the address.
Lol yeah I was stunned when i read it. Imagine someone randomly trying to crack any of the UTXO addresses, only to land on the private key of puzzle 120. Should be the luckiest creature in the entire universe. Not even exaggerating. Chances are slimmer than one in the number of entire atoms in the universe.