[Spambayes] Messages avoid training with the proxy version

[Katz, Amir]

I'm using SB at home with Thunderbird (TB), both latest versions, and
I've recently noticed something really weird.
 
1. I start TB, click on 'Get mail' button 
2. TB says '7 messages', then it goes on and downloads 7 messages. 
3. Next I go to the 'review messages' page of SB proxy, and there I see
only 3 untrained messages (some unsure, some ham, some spam). I do the
training.
4. Next I go back to TB and I see that those missing messages ended
right in my inbox (and they're usually spam, as I have filters that move
most of my good e-mail to other folders).
5. The numbers 7 and 3 are just example, but this has been happening
since I had to delete the database due to corruption.

One possibly important piece for the puzzle: I am running Avast
anti-virus that also filters incoming e-mails.

Any idea what's wrong?
 
Thanks

Amir