I don't think this is a JBoss related issue.
What happens if you "set -o notify" and then force a terminal session logout through "control D". I vaguely remember having this issue with AIX and I think the solution was to set notification to be asynchronous? Perhaps it was "set +o notify". AIX used to warn you that there were jobs running in the background.
Anyway try playing around with that and see if you have any success.