Yes, likely you're missing the rule_value setting.
Code:
mysql> SELECT * FROM rule_values WHERE rule_name LIKE 'Character:EnableDiscovere
dItems';
+------------+---------------------------------+------------+-------------------
-----------------------------------------------------------------------+
| ruleset_id | rule_name | rule_value | notes
|
+------------+---------------------------------+------------+-------------------
-----------------------------------------------------------------------+
| 1 | Character:EnableDiscoveredItems | true | If enabled, it ena
bles EVENT_DISCOVER_ITEM and also saves character names and timestamps |
+------------+---------------------------------+------------+-------------------
-----------------------------------------------------------------------+
1 row in set (0.00 sec)