This page details bugs of Jeopardy! (NES).
(Clue is at 4:13)
There is one clue in the game that will not accept the correct response: TV Twosomes - $200
NUMBER OF AGENT 86'S PARTNER ON TV'S *GET SMART*
Because 9 is used as a separator byte in the game, it gets parsed as a control character rather than being part of a player's response, meaning that even CPU opponents cannot get the money.