Gmail truncating attachments from MailScanner

[foulplay at foulplay.org]

Folks,

Attachments sent to a gmail address are ending up truncated. Yet, the same email to a non-gmail address shows up good. The “corruption” at gmail occurs when the email is sent in text format. HTML format works okay. So all my tests are focused on sending emails in text formats.

We are running Exim 4.90.1, MailScanner 5.0.7, ClamAV 0.99.4 and SpamAssassin 3.4.0. 

If we stop MailScanner and configure exim to deliver the mail directly, the attachment is viewable within gmail. 

Now the same setup/config files, except for older versions of all products (Exim 4.77, MailScanner 4.84.3, ClamAV 0.99.2 and SpamAssassin 3.3.1), gmail displays the attachment correctly. 

On one hand, the attachment is viewable when the same email is delivered to an address using Postfix and not within Gmail.
With MailScanner out of the equation, Gmail works.
Older versions of the setup works.
This is occurring across Thunderbird, Outlook and Apple Mail.

Although my troubleshooting has been limited on Hotmail, there too the attachments are showing corrupted.

I seem to be going around in circles between MailScanner and Gmail. Would appreciate any insight that might help me in troubleshooting this further.

Thanks
Avi