unable to block communication with unknown application categorie

Hello

My users have only access to Internet through HTTP, HTTPS, FTP and ICMP.

In Application control security profiles, I blocked Unknown applications.

This filter works well, but as you see, it sometimes allows unknown category sessions to pass like the following one . 

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Application Sensor     1 Name     HTTPS Application Category     unknown Protocol     tcp Service     HTTPS

Action Action     Accept: session close Security Action     Allowed Policy     9 Policy UUID     xxxxxxxxxx Policy Type     IPv4

#########################

what can I do to resolve this problem ?

Thank you.