Back with answer:
By default scanning of encrypted traffic is disabled, because it might cause conflicts with some applications which use SSL. Indeed, that checking looks like a little "hack", some browsers and mail clients which send and receive this traffic and do not refer to the system certificate storage, may need Doctor Web SSL certificate to operate. Some "properly written" software that checks their own certificates may not work at all.
So, don't rely too much on "Scan of encrypted traffic".
Thanks to Dmitry !
Have a great day!