Version: (using KDE KDE 3.5.6) Installed from: Debian testing/unstable Packages Reported in Debain BTS at http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=425427 There's a catch-all rule (that doesn't stop) that forwards a copy of all mails to another email. That, sometimes uses the local mta while it's not the default method. I've checked that all folders have the default sender identity too.
Sorry, but I can't make any sense of this bug report. Please describe exactly what happend (e.g. what you clicked, which steps you took and so on) and what should happen.
Without more information there's not much we can do. Reopen if you can fulfil Thomas' request for more info.