Do not use the members that have not been set(null).

Author: Cyperghost

wcfsetup/install/files/lib/system/cache/eager/AbstractEagerCache.class.php

@@ -54,8 +54,14 @@ private function getCacheKey(): string
 
             $parameters = [];
             foreach ($reflection->getProperties() as $property) {
-                $parameters[$property->getName()] = $property->getValue($this);
+                $value = $property->getValue($this);
+                if ($value === null) {
+                    continue;
+                }
+
+                $parameters[$property->getName()] = $value;
             }
+
             if ($parameters !== []) {
                 $this->cacheName .= '-' . CacheHandler::getInstance()->getCacheIndex($parameters);
             }