All actions in the game are made only after appropriate commands are sent by the players. If you send troops to a target, then they will surely arrive at it and not any other, as the game server performs the command that was sent from the game client. Your troops can reach another target only if the server receives another command. Moreover, the commands from the game client technically cannot be changed during the process of its delivering to the server. The troops-tracking system is a highly controlled element of the gameplay. Our QA team tested it thoroughly at all stages.
During many successive attacks, you can accidentally send your troops to the wrong target. So please ensure you have selected the correct target and troops before pressing the "Send" button.
Meanwhile, don't worry if your troops arrive at a different Persian Position. They will be counted toward your future rewards on the Persian Positions anyway.