there is no bug...
1st msf on BT4 is a regular svn build from the original one, that's why you should also
regularly update msf3, just execute2nd just read closely the howto's and do proper testing & logging to catch your issue.Code:sudo msfupdate
Start here: Metasploit Unleashed - Mastering the Framework >> 11 Maintaining access > Keylogging
3rd if you'd like to submit a bug, go the the right web page:
Metasploit Framework - Issues - Metasploit Redmine Interface