diff --git a/addons/account/models/account_move.py b/addons/account/models/account_move.py
index 9c9fc1fbb85..b405c724aba 100644
--- a/addons/account/models/account_move.py
+++ b/addons/account/models/account_move.py
@@ -2078,6 +2078,19 @@ class AccountMove(models.Model):
                                     ignore = False
                         if ignore:
                             del res[key]
+
+            # Convert float values to their "ORM cache" one to prevent different rounding calculations
+            for dict_key in res:
+                move_id = dict_key.get('move_id')
+                if not move_id:
+                    continue
+                record = self.env['account.move'].browse(move_id)
+                for fname, current_value in res[dict_key].items():
+                    field = self.env['account.move.line']._fields[fname]
+                    if isinstance(current_value, float):
+                        new_value = field.convert_to_cache(current_value, record)
+                        res[dict_key][fname] = new_value
+
             return res
 
         def dirty():
@@ -2111,17 +2124,18 @@ class AccountMove(models.Model):
         if needed_after == needed_before:
             return
 
-        to_delete = sorted({
+        to_delete = [
             line.id
             for key, line in existing_before.items()
             if key not in needed_after
             and key in existing_after
             and before2after[key] not in needed_after
-        } | {
-            line.id
+        ]
+        to_delete_set = set(to_delete)
+        to_delete.extend(line.id
             for key, line in existing_after.items()
-            if key not in needed_after
-        })
+            if key not in needed_after and line.id not in to_delete_set
+        )
         to_create = {
             key: values
             for key, values in needed_after.items()
diff --git a/addons/account/tests/test_account_move_out_invoice.py b/addons/account/tests/test_account_move_out_invoice.py
index e6f25fd6d4f..b4568c82d30 100644
--- a/addons/account/tests/test_account_move_out_invoice.py
+++ b/addons/account/tests/test_account_move_out_invoice.py
@@ -3558,3 +3558,22 @@ class TestAccountMoveOutInvoiceOnchanges(AccountTestInvoicingCommon):
         })
         invoice.action_post()
         self.assertEqual(invoice.name, 'INV1/2023/00010')
+
+    def test_invoice_mass_posting(self):
+        """
+        With some particular setup (in this case, rounding issue), partner get mixed up in the
+        invoice lines after mass posting.
+        """
+        currency = self.company_data['currency']
+        currency.rounding = 0.0001
+        invoice1 = self.init_invoice(move_type='out_invoice', partner=self.partner_a, invoice_date='2016-01-20', products=self.product_a)
+        invoice1.invoice_line_ids.price_unit = 12.36
+        invoice2 = self.init_invoice(move_type='out_invoice', partner=self.partner_b, invoice_date='2016-01-20', products=self.product_a)
+
+        vam = self.env["validate.account.move"].create({"force_post": True})
+        vam.with_context(active_model='account.move', active_ids=[invoice2.id, invoice1.id]).validate_move()
+
+        for aml in invoice1.line_ids:
+            self.assertEqual(aml.partner_id, self.partner_a)
+        for aml in invoice2.line_ids:
+            self.assertEqual(aml.partner_id, self.partner_b)