Expired records from the SpamAssassin cache

[Dan Carl]

Since a recent upgrade I am getting log entires like this:
    Expired 1 records from the SpamAssassin cache : 80 Time(s)
   
Can some explain what they are?

If my memory serves me right I this happened on a previous version and 
I fixed it by adding this cronjob.
30 0 * * * /usr/bin/sa-learn --force-expire
Do I still need to do this?
Thanks, 
ps
New Website looks very professional!