Undefined index: HTTPS in session443_form_user_login_alter() line 50

This error is showing up in the logs when someone (or bot) clicks the “log in to post comments” link.

https://example.com/user/login?destination=node%2F623%23comment-form

Notice: Undefined index: HTTPS in session443_form_user_login_alter() (line 50 of /html/sites/example.com/modules/session443/session443.module).

It only rises to the level of Notice so I guess I shouldn’t worry.

Sometimes the slash between node and the node ID is escaped, sometimes not.

I can force that Notice myself by entering bogus account info and failing the log in.

However, even though the error always precedes a failed log in attempt, sometimes that error appears without a failed log in notice. (And it’s not clear what precipitates it.)