seems that we got a nasty bug on the 1.2.3 version on the LiveStatus module. The module will crash (an be restart after few seconds) if the client close the socket without the server be really agree. It's due to log message refactoring during the 1.2.2 version.
You can look at the fix here http://www.shinken-monitoring.org/forum/index.php/topic,757.msg4185/boardseen.html
I'll surely release a 1.2.4 version soon. so if you got another bug, it's still time to report it :)