These are hidden fields included by CF7. To avoid that you’ll need to remove those fields from your final HTML, or ignore those fields in Basin.
Alright, this idea crossed my mind but I wanted to see if there was a more direct solution. I have no problem setting up the htaccess or netlify _redirects files myself, if there was an option to render the existing 404 page template page into a 404.html file (or 404/index.html file) that would work just fine for me
