diff --git a/addons/sale_stock_margin/models/sale_order_line.py b/addons/sale_stock_margin/models/sale_order_line.py
index c9cc59c55ef..16db4ef4242 100644
--- a/addons/sale_stock_margin/models/sale_order_line.py
+++ b/addons/sale_stock_margin/models/sale_order_line.py
@@ -7,7 +7,7 @@ from odoo import api, fields, models
 class SaleOrderLine(models.Model):
     _inherit = 'sale.order.line'
 
-    @api.depends('move_ids', 'move_ids.stock_valuation_layer_ids', 'order_id.picking_ids.state')
+    @api.depends('move_ids', 'move_ids.stock_valuation_layer_ids', 'move_ids.picking_id.state')
     def _compute_purchase_price(self):
         lines_without_moves = self.browse()
         for line in self:
diff --git a/addons/sale_stock_margin/tests/test_sale_stock_margin.py b/addons/sale_stock_margin/tests/test_sale_stock_margin.py
index 7fa377337aa..d153b53a762 100644
--- a/addons/sale_stock_margin/tests/test_sale_stock_margin.py
+++ b/addons/sale_stock_margin/tests/test_sale_stock_margin.py
@@ -166,6 +166,36 @@ class TestSaleStockMargin(TestStockValuationCommon):
         self.assertAlmostEqual(order_line_2.margin, 30)               # (20 - 12.5) * 4
         self.assertAlmostEqual(sale_order.margin, 64)
 
+    def test_sale_stock_margin_6(self):
+        """ Test that the purchase price doesn't change when there is a service product in the SO"""
+        service = self.env['product.product'].create({
+            'name': 'Service',
+            'type': 'service',
+            'list_price': 100.0,
+            'standard_price': 50.0})
+        self.product1.list_price = 80.0
+        self.product1.standard_price = 40.0
+        sale_order = self._create_sale_order()
+        order_line_1 = self._create_sale_order_line(sale_order, service, 1, 100)
+        order_line_2 = self._create_sale_order_line(sale_order, self.product1, 1, 80)
+
+        self.assertEqual(order_line_1.purchase_price, 50, "Sales order line cost should be 50.00")
+        self.assertEqual(order_line_2.purchase_price, 40, "Sales order line cost should be 40.00")
+
+        self.assertEqual(order_line_1.margin, 50, "Sales order line profit should be 50.00")
+        self.assertEqual(order_line_2.margin, 40, "Sales order line profit should be 40.00")
+        self.assertEqual(sale_order.margin, 90, "Sales order profit should be 90.00")
+
+        # Change the purchase price of the service product.
+        order_line_1.purchase_price = 100.0
+        self.assertEqual(order_line_1.purchase_price, 100, "Sales order line cost should be 100.00")
+
+        # Confirm the sales order.
+        sale_order.action_confirm()
+
+        self.assertEqual(order_line_1.purchase_price, 100, "Sales order line cost should be 100.00")
+        self.assertEqual(order_line_2.purchase_price, 40, "Sales order line cost should be 40.00")
+
     def test_so_and_multicurrency(self):
         ResCurrencyRate = self.env['res.currency.rate']
         company_currency = self.env.company.currency_id