I definitely fell for this one, but I was thinking more "Hmmm, seems odd to release an entirely new game when the current one is going strong."
The strangest April Fool's joke I've heard was when the BBC, in its usual matter-of-fact deadpan delivery calmly remarked that the spaghetti crops weren't going well this year, so the spaghetti prices would go up. They showed workers taking cooked spaghetti off trees.
A fairly large number of people fell for it, because it was the BBC pulling the prank, and at the time, in the UK, spaghetti was mainly distributed in cans, so many didn't really know where spaghetti came from.
I don't know if the reason "Why" is true, but that was an interesting April Fools joke.