The order of ActiveRecord callbacks matter when for example they need to access associations (e.g. has_many).
For example, the calculate_doors will be called before the associations are saved to the database if you use car.doors.build(name: :backdoor):
class Car < ApplicationRecord after_create :calculate_doors has_many :doors
This can lead to subtle errors.
Changing the order will fix the issue:
class Car < ApplicationRecord has_many :doors after_create :create_doors
Tested with Rails 6.1. Other versions might work differently.
Placing your callbacks after associations is usually a good practice.