Знаки вопроса увидел в ответе sockstat на FreeBSD 8.3
sockstat -4 | grep 3308
The question marks in sockstat are intended behaviour and not a bug.
The change between 8.2 and 8.3 is that sockstat now also shows sockets that are not associated with a file descriptor. Formerly, these were not shown, causing a discrepancy between sockstat and netstat -a because netstat has always shown them.