“OR” filter gives a 403 when selecting multiple options

Hello.

I’m implementing your filter plugin to our webshop. Everyhing seems to work, but with some terms when choosing multiple OR terms it displays Error 403

Forbidden

You don’t have permission to access this resource.

Strange thing is that with some other term the filter works perfect. The term permalink and URL VAR are different, but still throws the errror. Can you please check what could be the issue.

BR
Kaspar

The page I need help with: [log in to see the link]