Sql Local pb with secondary index

It seems that the using field defined as secondary index in sql
statement with 'or' operator produce an error.
Sample:
        select * from table
        where Field1="const1" or Field1="const2" produce a null result.

        select * from table
        where Field1 in ("const1", "const2")  produce a null result.

If Field1 is not a secondary index, the result is correct.

If anyone knows the problem or a solution, I will be very interesting by
his backgroud.
                                Best Regards