diff --git a/lib/src/validator.dart b/lib/src/validator.dart
index 88455bc9..5b524e6e 100644
--- a/lib/src/validator.dart
+++ b/lib/src/validator.dart
@@ -387,7 +387,7 @@ class ValidationException extends AngelHttpException {
             statusCode: 400,
             errors: (errors ?? <String>[]).toSet().toList(),
             stackTrace: StackTrace.current) {
-    if (errors != null) this.errors.addAll(errors);
+    if (errors != null) this.errors.addAll(errors.toSet());
   }
 
   @override