It's not a split planchet. The coin has been cut in half, horizontally, and it's a damaged/ altered coin. Not, and was never, an error, I'm sorry to say.
....and that's assuming it's genuine, which I can't confirm from the photos. The coin looks 'mushy' as to strike details; I'm suspicious.
If this is an accurate statement of events, then I'm afraid that your "coin" is counterfeit . . . . a fraudulent copy, unless it is marked as such, and I don't see that. Z
To confirm, try to take a photo of the "edge" of the two halves when you set them back together like they were before. Get it really in focus with good lighting. Z
