ClamAVModule and csv files in zip files

[Mick]

Hello.

I am currently running MailScanner which uses the clamavmodule.  The 
other day, I received 4 emails from ad-noreply at google.com and each of 
these emails has a )non-password protected) zip file and contained 
within each zip file was a file called report.csv.  However, MailScanner 
quarantined them even though clamscan reports that none of the zip files 
are infected.  Placing ad-no-reply at google.com in 
/etc/MailScanner/rules/virus-scan.rules results in those zip files as 
sent from ad-noreply at google.com now passing through unscanned but why 
were the files quarantined in the first place when clamscan says that 
they're uninfected?

Thanks,
Mick.