I created a filter in Thunderbird 14 on client A that, when a certain rule on incoming mail is satisfied, the same mail is forwarded to client B and C.

Matching mails received from A are always forwarded to B and C, and that's what I want. Though, when the mail on A has an attachment, it is also forwarded by B and C but the file they receive is corrupted. In my case the incoming file on A is a Word file of about 10kb in size; clients B and C receive a Word file of 27 bytes.

I think this could happen because the forward starts from A when the attachment is not yet completely downloaded. I'm not sure this is the cause, though. And I wouldn't have any idea for a fix.

Any idea about how to investigate or solve the issue?