[Qmail-scanner-general] Why would the result line show SA:0(?/?)

[turgut k. <tu...@ka...>]

Hello..

I often see scan logs saying  SA:0(?/?)  I am wondering why the question 
marks.

This is a PLESK 12.0.18 server, and I was testing some local.cf changes 
to spamassassin and I noticed that some mail was skipping the spam check.
For example:

qmail-scanner-queue.pl: qmail-scanner[5438]: 
Clear:RC:0(217.131.39.69):SA:0(?/?): 2.615015 3594898 
cen...@eb... cen...@BL... 
HATIRLATMA-EBSO_KOBİ_OKULU-UYUMSUZ_REKABET_SEMİNERİ 
<120...@eb...> 
1474455315.7315-1.pluto.kalfaoglu.net:1431 eortulu.jpg:172939 
orig-pluto.kalfaoglu.net14744552667975438:3594898 
1474455315.7315-0.pluto.kalfaoglu.net:301 duyuru.pdf:2484473

(I modified the mail addresses above) .. A user complained about getting 
these mails so I wrote a rule for it in local.cf, but some of these mass 
mailings are still sliding through.

The SA:0(?/?) does not happen every time; for most mails  it works fine, 
such as  SA:0(2.0/8.0)

Any ideas why it might skip some mails and check others?
Many thanks,  -turgut