this is a problem:
some code and now a link inside the code [url]http://www.google.com[/url]
as you can see, URL-tags get added automatically because of the URI but inside code-tags the html afterwards does show up the automatically added URL tags.
i haven't found where this is done, still looking.
i have checked if it is done by add_post function. but no it seems to be somewhere else.
so i guess it's done in postmarkup…!? a lot of parsing :-)