SA cache not expiring entries?

[Ken A]

On one server (FC4), the SA cache seemed to not be expiring entries.
I was still seeing cache hits in the log, but no expiries running 4.50.5
It grew to about 650Mb before I decided to nuke it and start over to 
reclaim RAM (../incoming is in a tmpfs).

I then installed the latest 4.50.12-2 from mailscanner.info and now I 
see the Expired entries again in the log so all is well.

I'm wondering if updating the box with yum might have done something:
The log shows these updates:

Dec 16 11:11:17 Updated: perl-IO-stringy.noarch 2.110-2
Dec 16 11:11:18 Updated: perl-TimeDate.noarch 1:1.16-3
Dec 16 11:11:19 Updated: perl-MailTools.noarch 1.67-1.fc4
Dec 16 11:11:20 Updated: perl-MIME-tools.noarch 5.417-2
Dec 16 11:11:20 Updated: perl-Convert-TNEF.noarch 0.17-4

Could any of these have been the culprit?
Perhaps I should tell YUM to leave perl modules alone, and just install 
those provided with MailScanner?

Or, any other ideas why MailScanner might suddenly stop expiring entries 
from the cache?

Thanks,
Ken
Pacific.Net