diff --git a/addons/stock/models/stock_lot.py b/addons/stock/models/stock_lot.py
index c0bdcaac4c68fe61d4fba99abb81aa97f9794c94..a11110bc1de399af5c698ba328fb1d61bf7ea90b 100644
--- a/addons/stock/models/stock_lot.py
+++ b/addons/stock/models/stock_lot.py
@@ -33,7 +33,7 @@ class StockLot(models.Model):
     company_id = fields.Many2one('res.company', 'Company', required=True, index=True, default=lambda self: self.env.company.id)
     delivery_ids = fields.Many2many('stock.picking', compute='_compute_delivery_ids', string='Transfers')
     delivery_count = fields.Integer('Delivery order count', compute='_compute_delivery_ids')
-    last_delivery_partner_id = fields.Many2one('res.partner', compute='_compute_delivery_ids')
+    last_delivery_partner_id = fields.Many2one('res.partner', compute='_compute_last_delivery_partner_id')
 
     @api.model
     def generate_lot_names(self, first_lot, count):
@@ -124,10 +124,16 @@ class StockLot(models.Model):
         for lot in self:
             lot.delivery_ids = delivery_ids_by_lot[lot.id]
             lot.delivery_count = len(lot.delivery_ids)
-            lot.last_delivery_partner_id = False
-            # If lot is serial, keep track of the latest delivery's partner
-            if lot.product_id.tracking == 'serial' and lot.delivery_count > 0:
-                lot.last_delivery_partner_id = lot.delivery_ids.sorted(key=attrgetter('date_done'), reverse=True)[0].partner_id
+
+    def _compute_last_delivery_partner_id(self):
+        serial_products = self.filtered(lambda l: l.product_id.tracking == 'serial')
+        delivery_ids_by_lot = serial_products._find_delivery_ids_by_lot()
+        (self - serial_products).last_delivery_partner_id = False
+        for lot in serial_products:
+            if lot.product_id.tracking == 'serial' and len(delivery_ids_by_lot[lot.id]) > 0:
+                lot.last_delivery_partner_id = self.env['stock.picking'].browse(delivery_ids_by_lot[lot.id]).sorted(key='date_done', reverse=True)[0].partner_id
+            else:
+                lot.last_delivery_partner_id = False
 
     @api.model_create_multi
     def create(self, vals_list):
diff --git a/addons/stock_dropshipping/models/stock.py b/addons/stock_dropshipping/models/stock.py
index 7e90b1f6767f74bcf7bdad377c78acd8538f64f1..af6a566c5a8bea6cfb44ae0f7ac600d785b05c0b 100644
--- a/addons/stock_dropshipping/models/stock.py
+++ b/addons/stock_dropshipping/models/stock.py
@@ -52,8 +52,8 @@ class StockPickingType(models.Model):
 class StockLot(models.Model):
     _inherit = 'stock.lot'
 
-    def _compute_delivery_ids(self):
-        super()._compute_delivery_ids()
+    def _compute_last_delivery_partner_id(self):
+        super()._compute_last_delivery_partner_id()
         for lot in self:
             if lot.delivery_count > 0:
                 last_delivery = max(lot.delivery_ids, key=lambda d: d.date_done)