Unusual requests triggering fatal errors

I’m seeing PHP fatal errors triggered by unexpected requests when the plugin is activated.

curl -v "http://localhost/?s=n&audience=x"

PHP Fatal error:  Uncaught TypeError: trim(): Argument #1 ($string) must be of type string, WP_Error given in /var/www/html/wp-content/plugins/wonderm00ns-simple-facebook-open-graph-tags/public/class-webdados-fb-open-graph-public.php:739
Stack trace:
 #0 /var/www/html/wp-content/plugins/wonderm00ns-simple-facebook-open-graph-tags/public/class-webdados-fb-open-graph-public.php(739): trim()
 #1 /var/www/html/wp-includes/class-wp-hook.php(341): Webdados_FB_Public->insert_meta_tags()
 #2 /var/www/html/wp-includes/class-wp-hook.php(365): WP_Hook->apply_filters()
 #3 /var/www/html/wp-includes/plugin.php(522): WP_Hook->do_action()
 #4 /var/www/html/wp-includes/general-template.php(3197): do_action()
 #5 /var/www/html/wp-content/themes/theme-child/templates/layouts/main.php(10): wp_head()
 #6 /var/www/html/wp-includes/template-loader.php(132): include('...')
 #7 /var/www/html/wp-blog-header.php(19): require_once('...')
 #8 /var/www/html/index.php(17): require('...')

The following line change – checking if $term->taxonomy is available before using it, seems to prevent the fatal error in this specific case.

--- a/public/class-webdados-fb-open-graph-public.php
+++ b/public/class-webdados-fb-open-graph-public.php
@@ -396,7 +396,7 @@ if ( ! class_exists( 'Webdados_FB_Public' ) ) :
                                                } elseif ( is_tax() ) {
                                                        $fb_title = wp_strip_all_tags( stripslashes( single_term_title( '', false ) ), true );
                                                        $term     = $wp_query->get_queried_object();
-                                                       $fb_url   = get_term_link( $term, $term->taxonomy );
+                                                       $fb_url   = ( isset( $term->taxonomy ) ) ? get_term_link( $term, $term->taxonomy ) : $fb_url;
                                                        $debug[]  = 'is_tax: ' . $term->taxonomy;
                                                        $tax_desc = trim( wp_strip_all_tags( stripslashes( term_description() ), true ) );
                                                        if ( '' != trim( $tax_desc ) ) {