diff --git a/app/models/customer.rb b/app/models/customer.rb
index a3baf79e6d..9d38bc7427 100644
--- a/app/models/customer.rb
+++ b/app/models/customer.rb
@@ -47,7 +47,7 @@ class Customer < ApplicationRecord
   def check_for_orders
     return true unless orders.any?
 
-    errors[:base] << I18n.t('admin.customers.destroy.has_associated_orders')
+    errors.add(:base, I18n.t('admin.customers.destroy.has_associated_orders'))
     throw :abort
   end
 end
diff --git a/app/models/spree/shipping_method.rb b/app/models/spree/shipping_method.rb
index 82dbee7e45..931186f28b 100644
--- a/app/models/spree/shipping_method.rb
+++ b/app/models/spree/shipping_method.rb
@@ -114,7 +114,7 @@ module Spree
     def at_least_one_shipping_category
       return unless shipping_categories.empty?
 
-      errors[:base] << "You need to select at least one shipping category"
+      errors.add(:base, "You need to select at least one shipping category")
     end
 
     def touch_distributors
diff --git a/app/models/spree/stock/availability_validator.rb b/app/models/spree/stock/availability_validator.rb
index 6c9516cd08..b4f6a9c4e0 100644
--- a/app/models/spree/stock/availability_validator.rb
+++ b/app/models/spree/stock/availability_validator.rb
@@ -46,9 +46,9 @@ module Spree
         variant = line_item.variant
         display_name = variant.name.to_s
         display_name += %{(#{variant.options_text})} if variant.options_text.present?
-        line_item.errors[:quantity] << Spree.t(:out_of_stock,
-                                               scope: :order_populator,
-                                               item: display_name.inspect)
+        line_item.errors.add(:quantity, Spree.t(:out_of_stock,
+                                        scope: :order_populator,
+                                        item: display_name.inspect))
       end
     end
   end