157b, responsive classic, PHP7.3

I turned on extra logging and this turned up, it is a notice so not an error; should I worry about it or ignore it?

Code:
[16-Apr-2021 22:14:00 Europe/Zurich] Request URI: /catalog/index.php?main_page=checkout_shipping, IP address: 88.151.150.xxx
#1 require_once(/includes/init_includes/init_sessions.php) called at [/includes/autoload_func.php:37]
#2 require(/includes/autoload_func.php) called at [/includes/application_top.php:219]
#3 require(/includes/application_top.php) called at [/index.php:25]
--> PHP Notice: Undefined index: SSL_SESSION_ID in /includes/init_includes/init_sessions.php on line 132.