Reading up on spamassassin

Last week our backup process almost took our mailserver down, not so good. But we managed to fix it. Unfortunately we had a small backlog on our queue that took a bit to catch up. Funny thing is that after restarting the spamassassin process, it seems to have difficulties to detect SPAM . Before the restart I almost didn’t receive any SPAM, now I had to lower my required score for SPAM. It seems it has forgotten some stuff it learned, very strange. So one of these nights, I’m gonna read up on the documentation seeing what could have gone wrong.

Anybody ever seen this phenomenon?