How Can I Change a Taxonomy URL Based On The Originating URL?

Question

The term_link filter has a different signature for its callback function than the page_link filter, meaning the arguments in your callback are different. (Also note you’ll need to explicitly set the argument number when you call add_filter because by default add_filter will only setup 1 argument. For example:

add_filter( 'term_link', 'lqd_series_link', 10, 3 ); // Where 3 is the number of arguments for your callback function

Then in your callback:

function lqd_series_link( $url, $term, $taxonomy ) {
    global $wp_query;
    if ( $taxonomy == 'gc-sermon-series' && isset( $wp_query->query_vars['app-view'] ) ) {
        return $url . 'app-view/';
    }
    return $url;
}