diff --git a/addons/purchase_stock/models/stock.py b/addons/purchase_stock/models/stock.py
index f578dff9f8a..0584e23b0b9 100644
--- a/addons/purchase_stock/models/stock.py
+++ b/addons/purchase_stock/models/stock.py
@@ -101,7 +101,8 @@ class StockMove(models.Model):
         self.write({'created_purchase_line_id': False})
 
     def _get_upstream_documents_and_responsibles(self, visited):
-        if self.created_purchase_line_id and self.created_purchase_line_id.state not in ('draft', 'done', 'cancel'):
+        if self.created_purchase_line_id and self.created_purchase_line_id.state not in ('done', 'cancel') \
+                and (self.created_purchase_line_id.state != 'draft' or self._context.get('include_draft_documents')):
             return [(self.created_purchase_line_id.order_id, self.created_purchase_line_id.order_id.user_id, visited)]
         elif self.purchase_line_id and self.purchase_line_id.state not in ('done', 'cancel'):
             return[(self.purchase_line_id.order_id, self.purchase_line_id.order_id.user_id, visited)]
diff --git a/addons/sale_purchase_stock/tests/__init__.py b/addons/sale_purchase_stock/tests/__init__.py
new file mode 100644
index 00000000000..ec59b790bc1
--- /dev/null
+++ b/addons/sale_purchase_stock/tests/__init__.py
@@ -0,0 +1,4 @@
+# -*- coding: utf-8 -*-
+# Part of Odoo. See LICENSE file for full copyright and licensing details.
+
+from . import test_sale_purchase_stock_flow
diff --git a/addons/sale_purchase_stock/tests/test_sale_purchase_stock_flow.py b/addons/sale_purchase_stock/tests/test_sale_purchase_stock_flow.py
new file mode 100644
index 00000000000..126f90bc3ad
--- /dev/null
+++ b/addons/sale_purchase_stock/tests/test_sale_purchase_stock_flow.py
@@ -0,0 +1,43 @@
+# -*- coding: utf-8 -*-
+# Part of Odoo. See LICENSE file for full copyright and licensing details.
+
+from odoo.tests.common import TransactionCase, Form
+
+
+class TestSalePurchaseStockFlow(TransactionCase):
+
+    def test_cancel_so_with_draft_po(self):
+        """
+        Sell a MTO+Buy product -> a PO is generated
+        Cancel the SO -> an activity should be added to the PO
+        """
+        mto_route = self.env.ref('stock.route_warehouse0_mto')
+        buy_route = self.env.ref('purchase_stock.route_warehouse0_buy')
+        mto_route.active = True
+
+        vendor = self.env['res.partner'].create({
+            'name': 'Super Vendor'
+        })
+
+        product = self.env['product.product'].create({
+            'name': 'SuperProduct',
+            'type': 'product',
+            'route_ids': [(6, 0, (mto_route + buy_route).ids)],
+            'seller_ids': [(0, 0, {
+                'partner_id': vendor.id,
+            })],
+        })
+
+        so_form = Form(self.env['sale.order'])
+        so_form.partner_id = self.env.user.partner_id
+        with so_form.order_line.new() as line:
+            line.product_id = product
+        so = so_form.save()
+        so.action_confirm()
+
+        po = self.env['purchase.order'].search([('partner_id', '=', vendor.id)])
+
+        so.action_cancel()
+
+        self.assertTrue(po.activity_ids)
+        self.assertIn(so.name, po.activity_ids.note)
diff --git a/addons/sale_stock/models/sale_order.py b/addons/sale_stock/models/sale_order.py
index 3a571fe7a50..d379d865ebf 100644
--- a/addons/sale_stock/models/sale_order.py
+++ b/addons/sale_stock/models/sale_order.py
@@ -191,7 +191,7 @@ class SaleOrder(models.Model):
         for sale_order in self:
             if sale_order.state == 'sale' and sale_order.order_line:
                 sale_order_lines_quantities = {order_line: (order_line.product_uom_qty, 0) for order_line in sale_order.order_line}
-                documents = self.env['stock.picking']._log_activity_get_documents(sale_order_lines_quantities, 'move_ids', 'UP')
+                documents = self.env['stock.picking'].with_context(include_draft_documents=True)._log_activity_get_documents(sale_order_lines_quantities, 'move_ids', 'UP')
         self.picking_ids.filtered(lambda p: p.state != 'done').action_cancel()
         if documents:
             filtered_documents = {}