I can confirm that both of these bugs still exist in 2.2.18
1. When one tries to change and save Server Settings all is fine, but the Zonefiles Dir field empties. I use FC6 and my path is /var/named/chroot/var/named
I could see /etc/bind in the form field (which is not correct in my case), but the corresponding field in the database is empty and not updating from ISPConfig.
I had to manually enter the correct path into the database field.
2. One of my clients accidentally entered host name with a .(dot), like 'host.', instead of 'host'. It broke named configuration.