Hi, I just want to share one of my observations. (Maybe a suggestion for future enhancements of luci interface.)
When you create a new inteface and configure IPv4 address (192.168.4.1 in my case) and forget to fill netmask (expecting default class C netmask will be used) it fills netmask of /32 (yes, 32) that totally confuses the DHCP server, that stops serving all other interfaces as well.
It would be nice if some meaningfull netmask is preset as default.