Activated DHCP Server on a Interface + bridge Interface ==> dhcp will be on
if you have set a dhcp server setting on the opt1 device and activate it, and after this you go into the device settings and select the bridge with LAN for example the dhcp server will not be deactivated and you can not select for example dhcp relay because of a running dhcpserver on an interface. you do not see on the dhcp server setup any longer, because of the bridge option on the interface.
you also will not get a message, when you bridge the interface that there are services on this interface. all option on an interface you want to bridge have to be deactivated.