bug in html-validator?

I think I found a bug in the Html validator....
This is what I did:
- go to http://validator.w3.org/
- type in the adress:
http://80.56.148.31:3000/php/discussie/advanced/een%20form.php?action=login&loginname=natahn
(this is my own server, so it won't be up when you try it)
- validated the page (it was correct)
- clicked on the URI for validation results below on the page
http://validator.w3.org/check?uri=http://80.56.148.31:3000/php/discussie/advanced/een%20form.php?action=login&loginname=natahn
- now the URI that's checked then, is 
http://80.56.148.31:3000/php/discussie/advanced/een%20form.php?action=login
so the last post variable (&loginname=natahn) is gone...

I'm not English so if you don't understand what I mean, you can mail me.

Nathan
nathan.b@12move.nl