Bullet is giving me a warning for has_one relationship

Question

I have the following code

class Tour < ApplicationRecord
    has_one :first_action, -> { order(scheduled_start_at: :desc) },
      class_name: 'TourAction',
      dependent: :nullify,
      inverse_of: :tour

   def date
     first_action.scheduled_start_at
   end

When I am exposing the date field on my grape entity

 expose(
      :date,
      documentation: {
        type: DateTime,
        desc: 'The date of the tour',
        example: '2023-03-07T10:54:10+01:00'
      }, format_with: :iso8601
    )

Bullet is giving me the use eager loading warning

2023-04-04 13:48:30[WARN] user: root
GET /api/v2/vehicles/2d836de7-27cb-4e64-854d-ad26d9063cc8/tours
USE eager loading detected
  Tour => [:first_action]
  Add to your query: .includes([:first_action])
  Call stack
/app/app/models/tour.rb:73:in `date'

How can I fix this?