Debian based OS's have a similar issue as the behavior in RHEL/CentOS dhclient, which is that if you have an interface that relies on DHCP, if the first attempt fails, it will quit and stop. This is a problem especially if you are using your Linux as a router or something else mission critical, but where the internet for some reason may have been down or the DHCP server it gets a lease from broken.
The expected behavior you would hope is that when things are back online that the........