After update to Patch Level 1:
InvalidArgumentException: Attempted to convert NULL to integer [content_id] in src/XF/Mvc/Entity/Entity.php at line 740
XF\Mvc\Entity\Entity->_castValueToType() in src/XF/Mvc/Entity/Entity.php at line 618
XF\Mvc\Entity\Entity->set() in src/XF/Mvc/Entity/Entity.php...