It appears qmail-toaster does headers differently. The received from unknown, not sure if a bug, or if that is how they set it up, since right after that it has the (helo hostname) IP.
It appears to be a regex problem in the perl script for spamassassin.
Using spamdyke protects you from this, so enable spamdyke and disable rdns none in spamassassin.
Find and Change /etc/spamassassin/local.cf:
score RDNS_NONE 0