DHCP Server stopped responding after switching TB to Ethernet Adapter
Probably your DHCP Server uses the wrong network interface to propagate the leases after building the bond:


Open Server.app and connect to your server
Click in the left pane on Advanced -> DHCP
Open the DHCP network in question by double-clicking on it or highlight it and click on the pencil at the bottom
Check the 'Network Interface'. Probably you still have an old network interface (Presumably Ethernet 0 or 1) chosen there. Change it to Bond0 (or whatever the human readable name is)
Hit the OK button and quit Server.app