Receive CanCan::AccessDenied error after modifying source code

Question

I'm StackOverFlow newcomer. Nice to meet you.

Now, I'm making EC Rails App with Spree Framework.

Spree admin role user is all fine.

But custom role user redirect to authentication_failure after modifying source code in TextEditor.

Process occur error is following:

1. Create custom user role colled 'sub_admin'.
2. Create user has 'sub_admin' role;
3. Log in with user has 'sub_admin' role;
4. Has no problem first time. It seems that all is fine.
5. Add code in model or controller file.（ex: add method, or change bit code）
6. Save code with ⌘+s on Editor.
7. Reload web page, recieve CanCan::AccessDenied and redirect to authentication_failure path.
8. Reboot rais server
9. Has no problem first time. It seems that all is fine.
10. 3~9 loop endless...

Admin role has no problem every time. Problem Only Occurs in custom role. Error that come is -

CanCan::AccessDenied error.

What's the matter?
I read documentation and Gem code, but I cannot get no idea or hint.

My ability file is following:
sub_admin_ability.rb

module Spree
  class SubAdminAbility
    include CanCan::Ability

    def initialize(user)
      user ||= Spree.user_class.new

      if user.sub_admin?
        can [:admin, :manage], Spree::Product
        can [:admin, :manage], Spree::Address
        can [:admin, :manage], Spree::Profile
        can [:admin, :manage], Spree::Image
        can [:admin, :create, :update, :addresses], Spree::User
      end
    end
  end
end

I use Gem version:

• spree 3.3.0
• spree_auth_devise 3.3.1
• spree_gateway 3.3.0

Thank you!

*add sign_out logs

Started GET "/logout" for xxx.xx.xx.xx at 2019-02-20 15:01:43 +0900
Cannot render console from xxx.xx.xx.xx! Allowed networks: 127.0.0.1, ::1, 127.0.0.0/127.255.255.255
Processing by Spree::UserSessionsController#destroy as HTML
  Spree::User Load (0.6ms)  SELECT  "spree_users".* FROM "spree_users" WHERE "spree_users"."deleted_at" IS NULL AND "spree_users"."id" = $1 ORDER BY "spree_users"."id" ASC LIMIT $2  [["id", 1], ["LIMIT", 1]]
  Spree::Preference Load (0.4ms)  SELECT  "spree_preferences".* FROM "spree_preferences" WHERE "spree_preferences"."key" = $1 LIMIT $2  [["key", "spree/app_configuration/currency"], ["LIMIT", 1]]
  Spree::Store Load (0.5ms)  SELECT  "spree_stores".* FROM "spree_stores" WHERE (url like '%localhost%') ORDER BY "spree_stores"."id" ASC LIMIT $1  [["LIMIT", 1]]
  Spree::Order Load (0.6ms)  SELECT  "spree_orders".* FROM "spree_orders" WHERE "spree_orders"."completed_at" IS NULL AND "spree_orders"."currency" = $1 AND "spree_orders"."guest_token" = $2 AND "spree_orders"."store_id" = $3 LIMIT $4  [["currency", "JPY"], ["guest_token", "dAvpS_lrpvdlbOxY2W6_RA1550053840935"], ["store_id", 1], ["LIMIT", 1]]
  Spree::Order Load (0.6ms)  SELECT  "spree_orders".* FROM "spree_orders" WHERE "spree_orders"."user_id" = $1 AND "spree_orders"."completed_at" IS NULL ORDER BY created_at DESC LIMIT $2  [["user_id", 1], ["LIMIT", 1]]
  Spree::LineItem Load (0.5ms)  SELECT "spree_line_items".* FROM "spree_line_items" WHERE "spree_line_items"."order_id" = 27 ORDER BY "spree_line_items"."created_at" ASC
  Spree::Variant Load (0.5ms)  SELECT "spree_variants".* FROM "spree_variants" WHERE "spree_variants"."deleted_at" IS NULL AND "spree_variants"."id" = 8
  Spree::Image Load (0.5ms)  SELECT "spree_assets".* FROM "spree_assets" WHERE "spree_assets"."type" IN ('Spree::Image') AND "spree_assets"."viewable_type" = $1 AND "spree_assets"."viewable_id" = 8 ORDER BY "spree_assets"."position" ASC  [["viewable_type", "Spree::Variant"]]
  Spree::OptionValueVariant Load (0.4ms)  SELECT "spree_option_value_variants".* FROM "spree_option_value_variants" WHERE "spree_option_value_variants"."variant_id" = 8
  Spree::OptionValue Load (0.4ms)  SELECT "spree_option_values".* FROM "spree_option_values" WHERE "spree_option_values"."id" = 2
  Spree::Product Load (0.7ms)  SELECT "spree_products".* FROM "spree_products" WHERE "spree_products"."deleted_at" IS NULL AND "spree_products"."id" = 5
  Spree::Order Load (0.6ms)  SELECT "spree_orders".* FROM "spree_orders" WHERE "spree_orders"."user_id" = $1 AND "spree_orders"."completed_at" IS NULL AND (id != 27)  [["user_id", 1]]
   (0.3ms)  BEGIN
   (0.3ms)  COMMIT
Redirected to http://localhost:3000/
Completed 302 Found in 36ms (ActiveRecord: 6.9ms)