HMS "Sussex" was an 80-gun third-rate ship of the line of the English Royal Navy, lost in a severe storm on 1 March 1694 off Gibraltar. On board were possibly 10 tons of gold coins. This could now be worth more than $500 million, including the bullion and antiquity values, making it one of the most valuable wrecks ever.
HMS "Sussex" left port on 1 March 1693.
The text does not state when the ship left port, but it had to happen sometime before it sank. The system seized upon the date that was slightly different than the one in the text as evidence that the statement was definitely incorrect.