Pigeonhole redirect is adding a message-id header when it already exists

[Marc]

> 
> 
> We are using sieve filter to redirect incoming mails to an external
> mailbox (gmail) an we are seeing some forwarded e-mails being rejected
> by gmail because of duplicate headers.
> 

How are you redirecting, like this[1]? I tested this ages ago. I am mostly testing with own gmail account, so  can't imagine this not working. It was an older 2.2 server I was testing this on.


[1]
if false # true
{
     redirect :copy "shit at gmail.com";
}