>
>I see your point. But I can't find where I am messing up.
>In short:
>the XML is populated in the ASP.NET method. Where each element of the XML is a value. The problem is that when the value for the dreaded TARG_DATE is '13/02/2019 ...' (note 13!) somewhere my code looks at this as an american date. But there is no month 13. And the error comes from the stored procedure (which I described above). But even when I comment what I think is "offending" line in the stored procedure, I still get an error.
>I am sure it is me.

How do you populate that XML? I think the problem lies in there. With a proper XML serialization TARG_DATE would never be 13/02/2019 nor 02/13/2019. And also it might help to see the SP code.