REST API, Updating Record, always returns The record has been changed by another user.

Edit Subject

Trying to update a issue field in a Record via REST API. I always get "The record has been changed by another user." Looking the SQL Profile, it includes the filed in the Where clause, because this is the field that I have updated and differs, it returns 0 records, hence getting the message. Any ideas how to resolve this?

Here is my code:
row.EmailContent = editor.getHtml();
$.ajax({
url: "http://localhost:14758/appservices/No...",
type: "PUT",
dataType: "jsonp",
data: row,
success: function (result) {
console.log(result);
}

});
});

Here is the generated SQL:
exec sp_executesql N'update "dbo"."NonConformanceEmailTemplate" set
"EmailContent"=@p0
where
"NonConformanceEmailTemplateID"=@p1
and "EmailContent" is null
',N'@p0 nvarchar(76),@p1 int',@p0=N'',@p1=3

I am trying to update Emailcontent field.