Besides the fact that I can't seem to figure out how to setup my rewrite rules for the search results url, I have another problem.
When a multiple filter query results in no found posts, I get a 404 error page instead of my archive.php template. As example:
correctly shows my archive template with the results and:
shows my 404.php template and not the 'no posts found' message in the archive.php template.
Any idea how to fix this?