Bug in Oracle 10g while using Check Constraint

Came across this bug in the check constraint in Oracle database 10g.
This has been tested in both 32 and 64 bit Oracle 10g (10.2.0.3) running on Windows 2003 Server.

SQL> select * from v$version;
BANNER
----------------------------------------------------------------
Oracle Database 10g Enterprise Edition Release 10.2.0.3.0 - Prod
PL/SQL Release 10.2.0.3.0 - Production
CORE 10.2.0.3.0 Production
TNS for 32-bit Windows: Version 10.2.0.3.0 - Production
NLSRTL Version 10.2.0.3.0 - Production

Reproducing the bug: Create a table called STORE having filed called LOCATION, this field should accept specified values or NULL values, below is the syntax:-

SQL> CREATE TABLE STORE (LOCATION VARCHAR2(15));

Table created.

SQL> ALTER TABLE STORE
2 ADD CONSTRAINT C1 CHECK
3 (LOCATION IN ('PHILLY','HARRISBURG',NULL));

Table altered.

Bug Note: By specifying a NULL, the constraint doesn't not verifies/validates the entered value.

SQL> INSERT INTO STORE VALUES ('PHILLY');
1 row created.

SQL> INSERT INTO STORE VALUES ('philly');
1 row created.

SQL> INSERT INTO STORE VALUES ('HARRISBURG');
1 row created.

SQL> INSERT INTO STORE VALUES ('harrisburg');
1 row created.

SQL> INSERT INTO STORE VALUES (null);
1 row created.

SQL> INSERT INTO STORE VALUES ('PITTSBURGH');
1 row created.

SQL> INSERT INTO STORE VALUES ('pittsburgh');
1 row created.

SQL> commit;
Commit complete.

SQL> col SEARCH_CONDITION for a50
SQL> select
2 STATUS,
3 DEFERRABLE,
4 DEFERRED,
5 VALIDATED,
6 SEARCH_CONDITION
7 FROM ALL_CONSTRAINTS A
8 WHERE table_name='STORE';

STATUS DEFERRABLE DEFERRED VALIDATED SEARCH_CONDITION
-------- -------------- --------- ------------- ----------------------------------------
ENABLED NOT DEFERRABLE IMMEDIATE VALIDATED LOCATION IN ('PHILLY','HARRISBURG',NULL)

SQL> select LOCATION from STORE;
LOCATION
---------------
PHILLY
philly
HARRISBURG
harrisburg

PITTSBURGH
pittsburgh

7 rows selected.

PROBLEM: DMLs like INSERT, UPDATE and DELETE works, but Query (SELECT) statements doesn't work in Oracle 10g (Tested in 10.2.0.3 both in 32 and 64 bit) while querying for records that actually violates the constraint rule. But works fine in Oracle 9i (tested in 9.2.0.8) and 11g (tested in 11.1.0.6)

Condition that violate the constraint rule:-
SQL> select count(*) from STORE where LOCATION='philly';

COUNT(*)
----------
0

Condition that doesn't violate the constraint rule:-
SQL> select count(*) from STORE where LOCATION='PHILLY';
COUNT(*)
----------
1

SQL> select count(*) from STORE where upper(LOCATION)=upper('philly');
COUNT(*)
----------
2

Condition that violate the constraint rule, DMLs works fine:-
SQL> update STORE set LOCATION='XYX' where LOCATION='philly';
1 row updated.

SQL> commit;
Commit complete.

Condition that violate the constraint rule:-
SQL> select count(*) from STORE where LOCATION='XYX';
COUNT(*)
----------
0

SQL> select LOCATION from STORE;
LOCATION
---------------
PHILLY
XYX
HARRISBURG
harrisburg

PITTSBURGH
pittsburgh

7 rows selected.

Condition that violate the constraint rule, DMLs works fine:-
SQL> delete from STORE where LOCATION='XYX';

1 row deleted.

SQL> select LOCATION from STORE;
LOCATION
---------------
PHILLY
HARRISBURG
harrisburg

PITTSBURGH
pittsburgh

6 rows selected.

SQL> commit;

Commit complete.

FIX for 10g

ALTER TABLE STORE drop CONSTRAINT C1 ;

Option # 1: Create a check constraint without specifying NULL. By default check constraint will accept NULL values, hence it doesn't have to be mentioned in the constraint condition

ALTER TABLE STORE
ADD CONSTRAINT C1 CHECK
(LOCATION IN ('PHILLY','HARRISBURG'));

or

ALTER TABLE STORE
ADD CONSTRAINT C1 CHECK
(LOCATION IN ('PHILLY','HARRISBURG') or LOCATION IS NULL);

Option # 2: Specify function like UPPER or LOWER in the constraint

ALTER TABLE STORE
ADD CONSTRAINT C1 CHECK
(UPPER(LOCATION) IN ('PHILLY','HARRISBURG'));

Option # 3: If NOT NULL need to be enforced along with the above condition, then use the following:-

ALTER TABLE STORE
ADD CONSTRAINT C1 CHECK
(LOCATION IN ('PHILLY','HARRISBURG') and LOCATION IS NOT NULL);

Did anyone else had similar problem?