migration error when deleting 2 or more related classes

That's my relevant schema.yml before changes:

Customer:
columns:
[..]

CustomerPlace:
columns:
[..]
relations:
Customer:
local: customer_id
foreignAlias: Addresses
onDelete: CASCADE

CustomerPerson:
columns:
[..]
relations:
CustomerPlace:
local: place_id
foreignAlias: Contacts
onDelete: CASCADE

I deleted all of the 3 entities, I executed symfony doctrine:generate-migrations-diff, which created the migration file containing:

    
        $this->dropTable('customer');
        $this->dropTable('customer_person');
        $this->dropTable('customer_place');

Executing the migration, gave me error for constrain violation. To fix the error, I added:

        $this->dropForeignKey('customer_person', 'customer_person_place_id_customer_place_id');
        $this->dropForeignKey('customer_place', 'customer_place_customer_id_customer_id');

Thanks.