Instantiating Objects in Wrong Scene

This is a recent and weird issue, but here's the layout of the game and where the problem lies.

Player 1
Scene 1: Players log in
Scene 2: Players choose character
Scene 3: Objects instantiate here into the game.

Player 2
Scene 1: Player logs in
Scene 2: Player chooses character, but the other players character is shown instantiated and animating in this scene?
Scene 3: In the same map where the other player is, there appears to be no one.

How can I make sure instantiated objects STAY in the map they instantiate for everyone?