Can someone explain what has happened here? I mined a block of 50 a while back, then I recently made a payment of .31 BTC. Why is the other 49.69 also in the transaction? This extra transaction does not show up in my wallet, but if I take an old backup and let it update, it does show up and the total block of 50 is missing.
https://blockchain.info/address/14sDPWsDWUdQCXWpJ4YVQYSxx9TFQh9STt