diff --git a/addons/web/static/src/js/views/form_relational_widgets.js b/addons/web/static/src/js/views/form_relational_widgets.js
index 2ca483eac2b..1dd61553ca2 100644
--- a/addons/web/static/src/js/views/form_relational_widgets.js
+++ b/addons/web/static/src/js/views/form_relational_widgets.js
@@ -264,6 +264,12 @@ var FieldMany2One = common.AbstractField.extend(common.CompletionFieldMixin, com
             }
         });
 
+        // avoid ignoring autocomplete="off" by obfuscating placeholder, see #30439
+        if (this.$input.attr('placeholder')) {
+            this.$input.attr('placeholder', function (index, val) {
+                return val.split('').join('\ufeff');
+            });
+        }
         var isSelecting = false;
         // autocomplete
         this.$input.autocomplete({