Unique:=True Argument in Range.AdvancedFilter Method not working properly

When I use the below code to paste the unique values from column a to b, the first value in column a is always getting repeated at the end of column b.

Sheet1.Range("A1:A10").AdvancedFilter Action:=xlFilterCopy, _
           CopyToRange:=Sheet1.Range("B1:B10"), Unique:=True

column A: test1,test2,test3,test1,test2,test3

column B: test1,test2,test3,test1

As shown above test1 is getting repeated. I tried changing the values, alter sequence in column a but still 1st value is getting repeated.