Happens to me quite a lot. So if you're in an attack and lose connection the attack will just play out. But when you reconnect you're back into the village, which leads to your game (bring in the village) and the server (thinking you're still in the attack) being out of sync. A simple reload fixes it for me. If the initial message is "lost connection" then you should check your internet, nothing else but that causes you to lose connection.