diff --git a/addons/sale_stock/tests/test_sale_stock.py b/addons/sale_stock/tests/test_sale_stock.py
index e69a454b45d..0fab4e26da5 100644
--- a/addons/sale_stock/tests/test_sale_stock.py
+++ b/addons/sale_stock/tests/test_sale_stock.py
@@ -1653,3 +1653,47 @@ class TestSaleStock(TestSaleCommon, ValuationReconciliationTestCommon):
         return_picking_2 = self.env['stock.picking'].browse(res['res_id'])
         return_picking_2.button_validate()
         self.assertEqual(return_wizard.product_return_moves.quantity, 1)
+
+    def test_2_steps_fixed_procurement_propagation_with_backorder(self):
+        """
+        When validating a picking (partially coming from a backorder) linked to 2 destinations moves in a 2-steps delivery,
+        stock.move.line should be created for the 2 OUT moves.
+        Steps:
+        - Warehouse with Outgoing Shipments in 2 steps and propagation of rule set to Fixed
+        - Create a SO with 3 Product X
+        - on PICK_1 picking: set 1 unit in done, validate and create a backorder
+        - Create a SO with 1 Product X
+        - on PICK_2 picking: set 3 units in done and validate
+        """
+        warehouse = self.company_data.get('default_warehouse')
+        warehouse.delivery_steps = 'pick_ship'
+        rule = warehouse.delivery_route_id.rule_ids.filtered(lambda r: r.procure_method == 'make_to_stock')[0]
+        rule.group_propagation_option = 'fixed'
+        fixedGroup = self.env['procurement.group'].create({})
+        rule.group_id = fixedGroup
+        self.env['stock.quant']._update_available_quantity(self.test_product_delivery, warehouse.lot_stock_id, 4)
+        # create a SO with 3 products
+        so1 = self._get_new_sale_order(product=self.test_product_delivery, amount=3)
+        so1.action_confirm()
+        pick1 = fixedGroup.stock_move_ids.filtered(lambda m: m.origin == so1.name)[0].picking_id
+        out1 = so1.picking_ids.filtered(lambda p: p.picking_type_id == warehouse.out_type_id)
+        # set 1 done on the PICK move
+        pick1.move_ids.write({'quantity': 1, 'picked': True})
+        res_dict = pick1.button_validate()
+        # create a backorder for the 2 remaining products
+        backorder_wizard = Form(self.env[(res_dict.get('res_model'))].with_context(res_dict['context'])).save()
+        backorder_wizard.process()
+        pick2 = pick1.backorder_ids[0]
+        self.assertEqual(out1.move_line_ids.quantity, 1)
+        # create another SO with 1 product
+        so2 = self._get_new_sale_order(product=self.test_product_delivery, amount=1)
+        so2.action_confirm()
+        # PICK move of this SO will increment the product quantity of the PICK backorder by 1
+        # PICK backorder is linked to out1 and out2
+        out2 = so2.picking_ids.filtered(lambda p: p.picking_type_id == warehouse.out_type_id)
+        pick2.move_ids.write({'quantity': 3, 'picked': True})
+        pick2.button_validate()
+        self.assertEqual(out1.state, 'assigned')
+        self.assertEqual(out1.move_line_ids.quantity, 3)
+        self.assertEqual(out2.state, 'assigned')
+        self.assertEqual(out2.move_line_ids.quantity, 1)
diff --git a/addons/stock/models/stock_move.py b/addons/stock/models/stock_move.py
index e884323e62a..b62a86d2452 100644
--- a/addons/stock/models/stock_move.py
+++ b/addons/stock/models/stock_move.py
@@ -1528,7 +1528,7 @@ Please change the quantity done or the rounding precision of your unit of measur
         return self.env['stock.quant']._get_available_quantity(self.product_id, location_id, lot_id=lot_id, package_id=package_id, owner_id=owner_id, strict=strict, allow_negative=allow_negative)
 
     def _get_available_move_lines_in(self):
-        move_lines_in = self.move_orig_ids.filtered(lambda m: m.state == 'done').mapped('move_line_ids')
+        move_lines_in = self.move_orig_ids.move_dest_ids.move_orig_ids.filtered(lambda m: m.state == 'done').mapped('move_line_ids')
 
         def _keys_in_groupby(ml):
             return (ml.location_dest_id, ml.lot_id, ml.result_package_id, ml.owner_id)