diff --git a/src/Caching/Attribute/Send304IfNotModified.php b/src/Caching/Attribute/Send304IfNotModified.php
index 4c4c21e..2d7e960 100644
--- a/src/Caching/Attribute/Send304IfNotModified.php
+++ b/src/Caching/Attribute/Send304IfNotModified.php
@@ -10,6 +10,7 @@
 
 use Attribute;
 use Exception;
+use InvalidArgumentException;
 use Webfactory\Bundle\WfdMetaBundle\Helper\LastmodHelper;
 use Webfactory\Bundle\WfdMetaBundle\MetaQueryFactory;
 
@@ -28,6 +29,10 @@ public function __construct(...$values)
             \E_USER_DEPRECATED
         );
 
+        if (!$values) {
+            throw new InvalidArgumentException(sprintf('The %s attribute needs at least one criterion', __CLASS__));
+        }
+
         $this->lastmodHelper = new LastmodHelper();
 
         foreach ($values as $key => $value) {
diff --git a/src/Caching/EventListener.php b/src/Caching/EventListener.php
index d06f907..1785642 100644
--- a/src/Caching/EventListener.php
+++ b/src/Caching/EventListener.php
@@ -109,7 +109,7 @@ protected function findAttribute($callback): ?Attribute\Send304IfNotModified
             $attributes = $method->getAttributes(\Webfactory\Bundle\WfdMetaBundle\Caching\Attribute\Send304IfNotModified::class);
 
             if ($attributes) {
-                return $attributes[0];
+                return $attributes[0]->newInstance();
             }
         }