diff --git a/addons/stock/models/stock_picking.py b/addons/stock/models/stock_picking.py
index 557f544cf38..a8083451bca 100644
--- a/addons/stock/models/stock_picking.py
+++ b/addons/stock/models/stock_picking.py
@@ -1245,16 +1245,10 @@ class Picking(models.Model):
         for picking in self:
             if picking.picking_type_id.create_backorder != 'ask':
                 continue
-            quantity_todo = {}
-            quantity_done = {}
-            for move in picking.move_ids.filtered(lambda m: m.state != "cancel"):
-                quantity_todo.setdefault(move.product_id.id, 0)
-                quantity_done.setdefault(move.product_id.id, 0)
-                quantity_todo[move.product_id.id] += move.product_uom._compute_quantity(move.product_uom_qty, move.product_id.uom_id, rounding_method='HALF-UP')
-                quantity_done[move.product_id.id] += move.product_uom._compute_quantity(move.quantity_done, move.product_id.uom_id, rounding_method='HALF-UP')
             if any(
-                float_compare(quantity_done[x], quantity_todo.get(x, 0), precision_digits=prec,) == -1
-                for x in quantity_done
+                    float_compare(move.quantity_done, move.product_uom_qty, precision_digits=prec) < 0
+                    for move in picking.move_ids
+                    if move.state != 'cancel'
             ):
                 backorder_pickings |= picking
         return backorder_pickings
diff --git a/addons/stock/tests/test_stock_flow.py b/addons/stock/tests/test_stock_flow.py
index cc6ab052f1d..53f941a280b 100644
--- a/addons/stock/tests/test_stock_flow.py
+++ b/addons/stock/tests/test_stock_flow.py
@@ -2643,3 +2643,36 @@ class TestStockFlowPostInstall(TestStockCommon):
         delivery.button_validate()
 
         self.assertEqual(sn.last_delivery_partner_id, partner)
+
+    def test_several_sm_with_same_product_and_backorders(self):
+        picking = self.env['stock.picking'].create({
+            'picking_type_id': self.picking_type_in,
+            'location_id': self.supplier_location,
+            'location_dest_id': self.stock_location,
+        })
+        move01, move02 = self.env['stock.move'].create([{
+            'name': self.productA.name,
+            'product_id': self.productA.id,
+            'product_uom_qty': 10,
+            'product_uom': self.productA.uom_id.id,
+            'description_picking': desc,
+            'picking_id': picking.id,
+            'location_id': self.supplier_location,
+            'location_dest_id': self.stock_location,
+        } for desc in ['Lorem', 'Ipsum']])
+
+        picking.action_confirm()
+
+        move01.quantity_done = 12
+        move02.quantity_done = 8
+
+        res = picking.button_validate()
+        self.assertIsInstance(res, dict)
+        self.assertEqual(res.get('res_model'), 'stock.backorder.confirmation')
+
+        wizard = Form(self.env[res['res_model']].with_context(res['context'])).save()
+        wizard.process()
+
+        backorder = picking.backorder_ids
+        self.assertEqual(backorder.move_ids.product_uom_qty, 2)
+        self.assertEqual(backorder.move_ids.description_picking, 'Ipsum')