Index: wp-admin/includes/class-wp-list-table.php
===================================================================
--- wp-admin/includes/class-wp-list-table.php	(revision 17186)
+++ wp-admin/includes/class-wp-list-table.php	(working copy)
@@ -852,7 +852,7 @@
 		else
 			$this->display_rows_or_placeholder();
 
-		$rows = ob_get_clean();
+		$rows = wp_check_invalid_utf8( ob_get_clean(), true );
 
 		$response = array( 'rows' => $rows );
 
Index: wp-includes/formatting.php
===================================================================
--- wp-includes/formatting.php	(revision 17186)
+++ wp-includes/formatting.php	(working copy)
@@ -473,8 +473,11 @@
 	}
 
 	// Attempt to strip the bad chars if requested (not recommended)
-	if ( $strip && function_exists( 'iconv' ) ) {
-		return iconv( 'utf-8', 'utf-8', $string );
+	if ( $strip ) {
+		if ( function_exists( 'iconv' ) )
+			return iconv( 'utf-8', 'utf-8//IGNORE', $string );
+		elseif ( function_exists( 'mb_convert_encoding' ) ) 
+			return mb_convert_encoding( $string, 'utf-8', 'utf-8' );
 	}
 
 	return '';