Issue with polymorphic associations

polymorphic.rb

class Task < ActiveRecord::Base
  has_one    :notification_preference, as: :notifee
  
  accepts_nested_attributes_for :notification_preference
end

class NotificationPreference < ActiveRecord::Base
  belongs_to :notifee, polymorphic: true  
end

# accepts_nested_attributes_for allows you to do this:
Task.find_or_initialize_by(
  notification_preference_attributes: {
    # attributes for the NP
  }
)