JoJo's Bizarre Adventure - When someone spoils you on something and act like you should already know it.

Fun Fact: When Stone Ocean was first released, specifically this part, Sixth Sense had not yet been released in Japan, as it had already been out for a while in the states. Araki literally spoiled the entire movie to his Japanese audience as a goof.

According to the japanese Wikipedia, The Sixth Sense was released in Japan in October 30th, 1999.
And according to the JoJo wiki, Jail House Lock part 4 (where this is from) was published in January 17, 2002.

So you're right, it's just a made-up rumor.