Thanks for bringing this to our attention!
It looks like the client-side handling of
SSH_MSG_CHANNEL_REQUEST packets in Rebex SSH does not conform to RFC 4254, and we will address that in the next release.
However, the proposed solution does not seem to be a proper one either. According to the comment in OpenSSH's server-side code where the
email@example.com is sent, the expected behavior for the SSH client is to simply respond with a
SSH_MSG_CHANNEL_FAILURE packet, which is also what RFC 4254 says.
So we'll address this in a standard-compliant way first. Hopefully, that would address the issues you discovered as well. If not, we would add a workaround later.