Actually, this is normal behaviour for netcat-openbsd. The man page is quite specific that -l and -p cannot be used together:
" -l Used to specify that nc should listen for an incoming connection rather than initiā ate a connection to a remote host. It is an error to use this option in conjunction with the -p, -s, or -z options. " -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org