diff --git a/addons/account/models/account_invoice.py b/addons/account/models/account_invoice.py
index 4fe54d0b77b..d492485c681 100644
--- a/addons/account/models/account_invoice.py
+++ b/addons/account/models/account_invoice.py
@@ -1154,11 +1154,11 @@ class AccountInvoiceLine(models.Model):
     account_analytic_id = fields.Many2one('account.analytic.account',
         string='Analytic Account')
     company_id = fields.Many2one('res.company', string='Company',
-        related='invoice_id.company_id', store=True, readonly=True)
+        related='invoice_id.company_id', store=True, readonly=True, related_sudo=False)
     partner_id = fields.Many2one('res.partner', string='Partner',
-        related='invoice_id.partner_id', store=True, readonly=True)
-    currency_id = fields.Many2one('res.currency', related='invoice_id.currency_id', store=True)
-    company_currency_id = fields.Many2one('res.currency', related='invoice_id.company_currency_id', readonly=True)
+        related='invoice_id.partner_id', store=True, readonly=True, related_sudo=False)
+    currency_id = fields.Many2one('res.currency', related='invoice_id.currency_id', store=True, related_sudo=False)
+    company_currency_id = fields.Many2one('res.currency', related='invoice_id.company_currency_id', readonly=True, related_sudo=False)
 
     @api.model
     def fields_view_get(self, view_id=None, view_type='form', toolbar=False, submenu=False):
diff --git a/addons/purchase/invoice.py b/addons/purchase/invoice.py
index 40705702e8b..ad3b1e0cec7 100644
--- a/addons/purchase/invoice.py
+++ b/addons/purchase/invoice.py
@@ -67,10 +67,7 @@ class AccountInvoice(models.Model):
             self.partner_id = self.purchase_id.partner_id.id
 
         new_lines = self.env['account.invoice.line']
-        for line in self.purchase_id.order_line:
-            # Load a PO line only once
-            if line in self.invoice_line_ids.mapped('purchase_line_id'):
-                continue
+        for line in self.purchase_id.order_line - self.invoice_line_ids.mapped('purchase_line_id'):
             data = self._prepare_invoice_line_from_po_line(line)
             new_line = new_lines.new(data)
             new_line._set_additional_fields(self)
@@ -198,5 +195,5 @@ class AccountInvoiceLine(models.Model):
     _inherit = 'account.invoice.line'
 
     purchase_line_id = fields.Many2one('purchase.order.line', 'Purchase Order Line', ondelete='set null', index=True, readonly=True)
-    purchase_id = fields.Many2one('purchase.order', related='purchase_line_id.order_id', string='Purchase Order', store=False, readonly=True,
+    purchase_id = fields.Many2one('purchase.order', related='purchase_line_id.order_id', string='Purchase Order', store=False, readonly=True, related_sudo=False,
         help='Associated Purchase Order. Filled in automatically when a PO is chosen on the vendor bill.')