Symfony 4.1 - Two EntityManagers. Migration goes twice on second EntityManager - symfony

Question

I've followed the directions on this page:
https://symfony.com/doc/current/doctrine/multiple_entity_managers.html
And my doctrine.yaml file looks like:
doctrine:
dbal:
default_connection: one
connections:
one:
# configure these for your database server
url: '%env(DATABASE_ONE_URL)%'
driver: 'pdo_mysql'
server_version: '5.7'
charset: utf8mb4
two:
# configure these for your database server
url: '%env(DATABASE_TWO_URL)%'
driver: 'pdo_mysql'
server_version: '5.7'
charset: utf8mb4
orm:
default_entity_manager: one
entity_managers:
one:
connection: one
mappings:
One:
is_bundle: false
type: annotation
dir: '%kernel.project_dir%/src/Entity/One'
prefix: 'App\Entity\One'
alias: One
two:
connection: two
mappings:
Two:
is_bundle: false
type: annotation
dir: '%kernel.project_dir%/src/Entity/Two'
prefix: 'App\Entity\Two'
alias: Two
I've got a One and Two directory inside my Entity directory with a simple Entity class in both:
A Person in One:
<?php
namespace App\Entity\One;
use Doctrine\ORM\Mapping as ORM;
/**
* #ORM\Entity
* #ORM\Table(name="person")
*/
class Person
{
/**
* #var int
*
* #ORM\Id
* #ORM\GeneratedValue(strategy="AUTO")
* #ORM\Column(type="integer")
*/
private $id;
/**
* #var string
*
* #ORM\Column(type="string")
*/
private $name;
{Getters and setters ...}
}
A Post in Two:
<?php
namespace App\Entity\Two;
use Doctrine\ORM\Mapping as ORM;
/**
* #ORM\Entity
* #ORM\Table(name="post")
*/
class Post
{
/**
* #var int
*
* #ORM\Id
* #ORM\GeneratedValue(strategy="AUTO")
* #ORM\Column(type="integer")
*/
private $id;
/**
* #var string
*
* #ORM\Column(type="string")
*/
private $title;
{Getters and setters ...}
}
When I run bin/console doctrine:migrations:diff and bin/console doctrine:migrations:migrate the Person is added to the One database correctly.
When I run bin/console doctrine:migrations:diff --em=two and bin/console doctrine:migrations:migrate --em=two both this and the Person migration for One are executed and the Two database has both a Person and a Page table.
I can't seem to figure out where I'm going wrong with this