Amavisd does not reject spammy emails

[Jussi Hirvi]

I recently noticed that my email server now delivers spam to final 
recipients even when the spam score is over $sa_kill_level_deflt.

My hypothesis is that some amavisd update has introduced new 
configuration variables, which I have not defined in my configuration, 
and the default value of some such variable causes this unwanted behavior.

I tried to go through documentation, but did not find the reason. Has 
anybody else had the same problem?

# amavisd -V
amavisd-new-2.8.0 (20120630)

My case is practically identical with this:

http://unix.stackexchange.com/questions/118430/spam-dont-get-rejected-from-amavisd

Though my full config might be different than his (I did not compare 
every config var).

Any ideas?

- Jussi