Error when opening form processor list

TypeError: Return value of Civi\ActionProvider\Condition\AbstractCondition::jsonSerialize() must be an instance of Civi\ActionProvider\Condition\mixed, array returned in Civi\ActionProvider\Condition\AbstractCondition->jsonSerialize() (line 159 of /var/www/html/vwvdev/sites/default/files/civicrm/ext/action-provider/Civi/ActionProvider/Condition/AbstractCondition.php).