Require login when using Any in dropdown

When I use query multiple taxonomies to include categories, tags and 1 custom taxonomy as a dropdown in a single widget, I get a strange error, if I don’t specify a value for all 3.

For example:
https://www.mysite.org/?category_name=cat&types=presentation&tag=

When the ‘tag=’ appears, I get an error saying i must be logged in and access denied. When I am logged in this doesn’t appear.
However if I search like this, when logged off:

For example:
https://www.mysite.org/?category_name=cat&types=presentation&tag=x
everything is fine!

Would anyone have any ideas how to tell the plugin to not put &tag= when it is set to Any?

https://www.ads-software.com/plugins/query-multiple-taxonomies/