This rumor seems to hold more credence than most, however.
At this point, we get a new release date leak for Red Dead Redemption 2 from retailers like once a week. So of course, we have another one for you today- but this one comes from a rather reputable retailer, so we probably have reason to put some stock in it.
According to a listing made by Media Markt, also known as Media World, and one of the largest, most respected retailers in Italy (and the second largest retailer of electronics in the world, after only Best Buy), it seems as though the game may be targeting an October 2 release date. October 2 is a Tuesday, and it is in the Fall- so the rumor makes sense. What gives it even more credence is the fact that the listing was changed very quickly to have a release date of December 31. You can check out a screencap of the original listing below, however.
So- honest mistake rectified to prevent people from getting the wrong idea? Or did they hit close to home? We should know soon enough.