diff --git a/addons/sale_timesheet/models/sale_order.py b/addons/sale_timesheet/models/sale_order.py
index 1e1df8677a7..940fe7390ef 100644
--- a/addons/sale_timesheet/models/sale_order.py
+++ b/addons/sale_timesheet/models/sale_order.py
@@ -327,6 +327,12 @@ class SaleOrderLine(models.Model):
                     map_so_project_templates[(so_line.order_id.id, so_line.product_id.project_template_id.id)] = project
                 else:
                     map_so_project[so_line.order_id.id] = project
+            elif not project:
+                # Attach subsequent SO lines to the created project
+                so_line.project_id = (
+                    map_so_project_templates.get((so_line.order_id.id, so_line.product_id.project_template_id.id))
+                    or map_so_project.get(so_line.order_id.id)
+                )
             if so_line.product_id.service_tracking == 'task_new_project':
                 if not project:
                     if so_line.product_id.project_template_id:
diff --git a/addons/sale_timesheet/tests/test_sale_service.py b/addons/sale_timesheet/tests/test_sale_service.py
index e13dd6c56c0..b1a65796fa6 100644
--- a/addons/sale_timesheet/tests/test_sale_service.py
+++ b/addons/sale_timesheet/tests/test_sale_service.py
@@ -363,8 +363,8 @@ class TestSaleService(TestCommonSaleTimesheetNoChart):
         # check each line has or no generate something
         self.assertTrue(so_line1.project_id, "Line1 should have create a project based on template A")
         self.assertTrue(so_line2.project_id, "Line2 should have create an empty project")
-        self.assertFalse(so_line3.project_id, "Line3 should not have create a project, since line1 already create a project based on template A")
-        self.assertFalse(so_line4.project_id, "Line4 should not have create a project, since line1 already create an empty project")
+        self.assertEqual(so_line3.project_id, so_line1.project_id, "Line3 should reuse project of line1")
+        self.assertEqual(so_line4.project_id, so_line2.project_id, "Line4 should reuse project of line2")
         self.assertTrue(so_line4.task_id, "Line4 should have create a new task, even if no project created.")
         self.assertTrue(so_line5.project_id, "Line5 should have create a project based on template B")