Bug in upgrade script in 6.3.5

After updating to v6.3.5 I got an error in the backend. In upgrade.php:958/959 you get an option which does not exist in my database, so that probably returns false and then you try to access a value from the variable which would normally be an array.
$settings = get_option( 'complianz_options_settings' );
$settings['safe_mode'] = $settings['disable_cookie_block'];

Problem does not occur in 6.3.4