Filtered non-clustered Index abnormal behaivior

I have a table that created some filtered non-clustered on some columns such:

CREATE UNIQUE NONCLUSTERED INDEX [IX_Sh_Esh] ON [dbo].[My_Tbl] 
(
    [City_Code] ASC,
[Sh_Esh] ASC
)
WHERE ([Sh_Bod]=(0) AND [Noe_Fa]=(0))
WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, SORT_IN_TEMPDB = OFF,            IGNORE_DUP_KEY = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
    GO

and:

CREATE UNIQUE NONCLUSTERED INDEX [IX_Kho] ON [dbo].[My_Tbl] 
(
[City_Code] ASC,
[Kho] ASC
)
WHERE ([Sh_Bod]=(0) AND [Sh_Esh]=(0) AND [Noe_Fa]=(1))
WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, SORT_IN_TEMPDB = OFF,     IGNORE_DUP_KEY = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
GO

I create this indexes on my table with no error but when I want to add a new column I get this error:

'My_Tbl' table
- Unable to create index 'IX_Sh_Esh'.  
The CREATE UNIQUE INDEX statement terminated because a duplicate key was found for the object name 'My_Tbl' and the index name 'IX_Sh_Esh'. The duplicate key value is (3, 0).

The statement has been terminated.

my table data is:

According to first Index because the rows No. 1 a开发者_开发技巧nd No. 4 does not satisfy the where cluase should not create index on them.Why I get the above error?

thanks

EDIT 1) :

there is Interesting point.If I delete that index and add the Column(s) then ReCreate that Index,the index create with no error.STRANGE!!!!

The reason you can drop the index and then add the data, then recreate the index is because creating an index does not check existing data, just data that you are trying to insert/update.

You're not getting the error because its a filtered index, you're getting it because its a unique index and you're trying to add duplicate values to the table's column that the unique index is on. That's the beaty of them! If you need duplicate data don't make the index unique.