diff --git a/app/models/spree/order_decorator.rb b/app/models/spree/order_decorator.rb
index 948cfc494a..b09408ba67 100644
--- a/app/models/spree/order_decorator.rb
+++ b/app/models/spree/order_decorator.rb
@@ -17,6 +17,14 @@ Spree::Order.class_eval do
   has_one :proxy_order
   has_one :subscription, through: :proxy_order
 
+  # This removes "inverse_of: source" which breaks shipment adjustment calculations
+  #   This change is done in Spree 2.1 (see https://github.com/spree/spree/commit/3fa44165c7825f79a2fa4eb79b99dc29944c5d55)
+  #   When OFN gets to Spree 2.1, this can be removed
+  has_many :adjustments,
+    as: :adjustable,
+    dependent: :destroy,
+    order: "#{Spree::Adjustment.table_name}.created_at ASC"
+
   validates :customer, presence: true, if: :require_customer?
   validate :products_available_from_new_distribution, :if => lambda { distributor_id_changed? || order_cycle_id_changed? }
   validate :disallow_guest_order
diff --git a/app/models/spree/payment_decorator.rb b/app/models/spree/payment_decorator.rb
index 8aab22a7bb..cd78e2b155 100644
--- a/app/models/spree/payment_decorator.rb
+++ b/app/models/spree/payment_decorator.rb
@@ -32,11 +32,7 @@ module Spree
 
     # This is called by the calculator of a payment method
     def line_items
-      if order.complete? && Spree::Config[:track_inventory_levels]
-        order.line_items.select { |li| inventory_units.pluck(:variant_id).include?(li.variant_id) }
-      else
-        order.line_items
-      end
+      order.line_items
     end
 
     # Pin payments lacks void and credit methods, but it does have refund
diff --git a/app/models/spree/shipment_decorator.rb b/app/models/spree/shipment_decorator.rb
index 625cf06dec..e9cdc1ed31 100644
--- a/app/models/spree/shipment_decorator.rb
+++ b/app/models/spree/shipment_decorator.rb
@@ -2,8 +2,12 @@ module Spree
   Shipment.class_eval do
     def ensure_correct_adjustment_with_included_tax
       ensure_correct_adjustment_without_included_tax
-      return unless adjustment
 
+      update_adjustment_included_tax if adjustment
+    end
+    alias_method_chain :ensure_correct_adjustment, :included_tax
+
+    def update_adjustment_included_tax
       if Config.shipment_inc_vat && (order.distributor.nil? || order.distributor.charges_sales_tax)
         adjustment.set_included_tax! Config.shipping_tax_rate
       else
@@ -11,8 +15,6 @@ module Spree
       end
     end
 
-    alias_method_chain :ensure_correct_adjustment, :included_tax
-
     private
 
     # NOTE: This is an override of spree's method, needed to allow orders
diff --git a/spec/factories.rb b/spec/factories.rb
index e5f785b439..b7129ee5f6 100644
--- a/spec/factories.rb
+++ b/spec/factories.rb
@@ -382,18 +382,6 @@ FactoryBot.define do
         shipment.add_shipping_method(evaluator.shipping_method, true)
       end
     end
-
-    trait :shipping_fee do
-      transient do
-        shipping_fee 3
-      end
-
-      after(:create) do |shipment, evaluator|
-        shipping_method = create(:shipping_method_with, :shipping_fee, shipping_fee: evaluator.shipping_fee)
-        shipment.shipping_rates.destroy_all
-        shipment.add_shipping_method(shipping_method, true)
-      end
-    end
   end
 
   factory :distributor_enterprise_with_tax, parent: :distributor_enterprise do
@@ -407,16 +395,16 @@ FactoryBot.define do
       payment_fee 5
     end
 
-    shipments { [ create(:shipment_with, :shipping_fee, shipping_fee: shipping_fee) ] }
+    ship_address { create(:address) }
 
     after(:create) do |order, evaluator|
+      create(:shipping_method_with, :shipping_fee, shipping_fee: evaluator.shipping_fee)
+
       create(:line_item, order: order)
       payment_calculator = build(:calculator_per_item, preferred_amount: evaluator.payment_fee)
       payment_method = create(:payment_method, calculator: payment_calculator)
       create(:payment, order: order, amount: order.total, payment_method: payment_method, state: 'checkout')
 
-      # skip the rebuilding of order.shipments from line_items and stock locations (this is enforced in checkout step :address to :delivery)
-      order.stub(:create_proposed_shipments)
       while !order.completed? do break unless order.next! end
     end
   end
diff --git a/spec/models/spree/order_spec.rb b/spec/models/spree/order_spec.rb
index e545127570..04303a8963 100644
--- a/spec/models/spree/order_spec.rb
+++ b/spec/models/spree/order_spec.rb
@@ -655,7 +655,8 @@ describe Spree::Order do
   end
 
   describe "a completed order with shipping and transaction fees" do
-    let(:order) { create(:completed_order_with_fees, shipping_fee: shipping_fee, payment_fee: payment_fee) }
+    let(:distributor) { create(:distributor_enterprise_with_tax) }
+    let(:order) { create(:completed_order_with_fees, distributor: distributor, shipping_fee: shipping_fee, payment_fee: payment_fee) }
     let(:shipping_fee) { 3 }
     let(:payment_fee) { 5 }
     let(:item_num) { order.line_items.length }
@@ -760,7 +761,7 @@ describe Spree::Order do
       it "returns previous items" do
         prev_order.add_variant(product.master, 1, 3)
         prev_order2.reload # to get the right response from line_items
-        expect(order.finalised_line_items.length).to eq 3
+        expect(order.finalised_line_items.length).to eq 11
         expect(order.finalised_line_items).to match_array(prev_order.line_items + prev_order2.line_items)
       end
     end