Decimal value with no decimal place is converted to string in generated sql when value goes beyond integer max or min value

I am using NH 3.0 with fluent mapping.

Here is the linq query:

var query = from invoice in db
where invoice.TotalAmount == totalAmount
select invoice;

"invoice.TotalAmount" and "totalAmount" are both defined as decimal.

Here are the input decimal values and corresponding generated sql:

-------------------------------------------- decimal totalAmount = int.MaxValue;

select <blah blah>
from RadiantBilling.dbo.Invoice invoice0_
where invoice0_.TotalAmount = 2147483647 /* @p0 */

>>> CORRECT <<<
-------------------------------------------- decimal totalAmount = decimal.Add(int.MaxValue, 1);

select <blah blah>
from RadiantBilling.dbo.Invoice invoice0_
where invoice0_.TotalAmount = '2147483648' /* @p0 */

>>> WRONG <<<
-------------------------------------------- decimal totalAmount = decimal.Add(int.MaxValue, 1.0M);

select <blah blah>
from RadiantBilling.dbo.Invoice invoice0_
where invoice0_.TotalAmount = 2147483648.0 /* @p0 */

>>> CORRECT <<<
-------------------------------------------- decimal totalAmount = int.MinValue;

select <blah blah>
from RadiantBilling.dbo.Invoice invoice0_
where invoice0_.TotalAmount = -2147483648 /* @p0 */

>>> CORRECT <<<
-------------------------------------------- decimal totalAmount = decimal.Add(int.MinValue, -1);

select <blah blah>
from RadiantBilling.dbo.Invoice invoice0_
where invoice0_.TotalAmount = '-2147483649' /* @p0 */

>>> WRONG <<<
--------------------------------------------