Change in whitelist behavior with 1.3.49

I just upgraded from 1.3.25 to 1.3.49, and the IP whitelisting has 
changed, marking a whole lot of mail as whitelisted that never used to be. 
I use a perl script that feeds incoming mail through dccifd, and I'm 
seeing reports like this:

X-DCC-IECC-Metrics: tom.iecc.com 1107; IP=ok Body=1 Fuz1=many Fuz2=many

As far as I can tell, none of the IPs in the message headers match any of 
the IPs in the whitelist files.  How can I even tell what IP it thinks 
it's whitelisting?

Regards,
John Levine, johnl@iecc.com, Primary Perpetrator of "The Internet for Dummies",
Information Superhighwayman wanna-be, http://www.johnlevine.com, Mayor
"More Wiener schnitzel, please", said Tom, revealingly.