Only one author displaying

The following code was working perfectly until recently. Now only one of the two authors is being displayed, as you can see in this page:
https://cdas.com/swatch-group-management-services-ltd-v-bloomberg-lp/

I am using it in a child theme built on Twentytwelve.
The code is a pretty long function as author names need to link to special bio pages and some authors are not part of the website and therefor don’t have a bio page (so no link for them).

if ( ! function_exists( 'twentytwelve_entry_meta' ) ) :
	function twentytwelve_entry_meta() {
		// Translators: used between list items, there is a space after the comma.
		$categories_list = get_the_category_list( __( ', ', 'twentytwelve' ) );

		// Translators: used between list items, there is a space after the comma.
		$tag_list = get_the_tag_list( '', __( ', ', 'twentytwelve' ) );

		$date = sprintf( '<a href="%1$s" title="%2$s" rel="bookmark"><time class="entry-date" datetime="%3$s">%4$s</time></a>',
			esc_url( get_permalink() ),
			esc_attr( get_the_time() ),
			esc_attr( get_the_date( 'c' ) ),
			esc_html( get_the_date() )
		);

		if(function_exists('coauthors')) {
		    $i = new CoAuthorsIterator();
		    $i->iterate();
		    $author = '';
		    do{
		      if (!$i->is_first()) $author .= $i->is_last() ? ' a ' : ', ';
		      	$authorid= get_the_author_meta( 'ID' );

				if(user_can($authorid, not_have_bio)) {
		        	$author .= sprintf( '<span class="author vcard">%1$s</span>',
		            get_the_author()
		            );
		            }else{
					$author = sprintf( '<span class="author vcard"><a class="url fn n" href="%1$s" title="%2$s" rel="author">%3$s</a></span>',
					//esc_url( get_author_posts_url( get_the_author_meta( 'ID' ) ) ),
					esc_url( get_the_author_meta( 'user_url' ) ),
					esc_attr( sprintf( __( 'View all posts by %s', 'twentytwelve' ), get_the_author() ) ),
					get_the_author()
					);
				}
		    } while($i->iterate());
		 	} else {

				$authorid= get_the_author_meta( 'ID' );

				if(user_can($authorid, not_have_bio)) {
		 			$author .= sprintf( '<span class="author vcard">%1$s</span>',
		            get_the_author()
		            );
				}else{
					$author = sprintf( '<span class="author vcard"><a class="url fn n" href="%1$s" title="%2$s" rel="author">%3$s</a></span>',
					//esc_url( get_author_posts_url( get_the_author_meta( 'ID' ) ) ),
					esc_url( get_the_author_meta( 'user_url' ) ),
					esc_attr( sprintf( __( 'View all posts by %s', 'twentytwelve' ), get_the_author() ) ),
					get_the_author()
					);
				}
		}

		// Translators: 1 is category, 2 is tag, 3 is the date and 4 is the author's name.
		if ( $tag_list ) {
			$utility_text = __( 'This entry was posted in %1$s and tagged %2$s on %3$s<span class="by-author"> by %4$s</span>.', 'twentytwelve' );
		} elseif ( $categories_list ) {
			$utility_text = __( 'This entry was posted in %1$s on %3$s<span class="by-author"> by %4$s</span>.', 'twentytwelve' );
		} else {
			$utility_text = __( 'This entry was posted on %3$s<span class="by-author"> by %4$s</span>.', 'twentytwelve' );
		}

		printf(
			$utility_text,
			$categories_list,
			$tag_list,
			$date,
			$author
		);
	}
endif;

Thank you so very much for your help.

mkoenen

https://www.ads-software.com/plugins/co-authors-plus/