We have this issue too since the update. We are running Wasteland and Blitzkrieg type servers and they keep crashing about every 30 minutes. Server just crashes and clients either crash too or get the "Not received message since" red message.

Not a coincidence, the issue started after this morning update.

This is a server crash issue, this is a duplicate of this post here: http://feedback.arma3.com/view.php?id=5956

The issue is that the server crashes every 10-30 minutes. The reason why they come back up is that servers like mine are on auto-restart so they come back online if they crash.