[Ghosted]

1. Maybe player left game before task was executed?
So you should use is_user_connected in checkdead
2. Use putinserver and not connect

public checkdead(id)
{
if(!is_user_connected(id) || is_user_alive(id))
return;

new Team = cs_get_user_team(id);

if (Team < 1 || Team > 2)
return;

/// Player is ready for spawning, your code here
}

EDIT (2): in set_task you should pass playerIndex (id) as task id, if you need infinity in set_task then you should use remove_task(id) in client disconnect/disconnected forward