diff --git a/app/services/cart_service.rb b/app/services/cart_service.rb
index 35dcb720f0..c4f3b5a5c0 100644
--- a/app/services/cart_service.rb
+++ b/app/services/cart_service.rb
@@ -106,13 +106,15 @@ class CartService
   end
 
   def read_variants_hash(data)
-    (data[:variants] || []).map do |variant_id, quantity|
-      if quantity.is_a?(Hash)
-        { variant_id: variant_id, quantity: quantity[:quantity], max_quantity: quantity[:max_quantity] }
+    variants_array = []
+    (data[:variants] || []).each do |variant_id, quantity|
+      if quantity.is_a?(ActionController::Parameters)
+        variants_array.push({ variant_id: variant_id, quantity: quantity[:quantity], max_quantity: quantity[:max_quantity] })
       else
-        { variant_id: variant_id, quantity: quantity }
+        variants_array.push({ variant_id: variant_id, quantity: quantity })
       end
     end
+    variants_array
   end
 
   def cart_remove(variant_id)
diff --git a/spec/services/cart_service_spec.rb b/spec/services/cart_service_spec.rb
index b8144f867b..51e8f2b882 100644
--- a/spec/services/cart_service_spec.rb
+++ b/spec/services/cart_service_spec.rb
@@ -27,7 +27,8 @@ describe CartService do
     describe "#populate" do
       it "adds a variant" do
         cart_service.populate(
-          { variants: { variant.id.to_s => { quantity: '1', max_quantity: '2' } } },
+          ActionController::Parameters.new({ variants: { variant.id.to_s => { quantity: '1',
+                                                                              max_quantity: '2' } } }),
           true
         )
         li = order.find_line_item_by_variant(variant)
@@ -41,7 +42,8 @@ describe CartService do
         order.add_variant variant, 1, 2
 
         cart_service.populate(
-          { variants: { variant.id.to_s => { quantity: '2', max_quantity: '3' } } },
+          ActionController::Parameters.new({ variants: { variant.id.to_s => { quantity: '2',
+                                                                              max_quantity: '3' } } }),
           true
         )
         li = order.find_line_item_by_variant(variant)
@@ -54,7 +56,7 @@ describe CartService do
       it "removes a variant" do
         order.add_variant variant, 1, 2
 
-        cart_service.populate({ variants: {} }, true)
+        cart_service.populate(ActionController::Parameters.new({ variants: {} }), true)
         order.line_items.reload
         li = order.find_line_item_by_variant(variant)
         expect(li).not_to be
@@ -67,7 +69,7 @@ describe CartService do
           it "does not add the deleted variant to the cart" do
             variant.delete
 
-            cart_service.populate({ variants: { variant.id.to_s => { quantity: '2' } } }, true)
+            cart_service.populate(ActionController::Parameters.new({ variants: { variant.id.to_s => { quantity: '2' } } }), true)
 
             expect(relevant_line_item).to be_nil
             expect(cart_service.errors.count).to be 0
@@ -82,7 +84,7 @@ describe CartService do
           it "removes the line_item from the cart" do
             variant.delete
 
-            cart_service.populate({ variants: { variant.id.to_s => { quantity: '3' } } }, true)
+            cart_service.populate(ActionController::Parameters.new({ variants: { variant.id.to_s => { quantity: '3' } } }), true)
 
             expect(Spree::LineItem.where(id: relevant_line_item).first).to be_nil
             expect(cart_service.errors.count).to be 0