Since we got our first SRX320 in replacement of our former SRX210 (R.I.P.), we trying to figure out why the DHCP server works for some devices (like PCs and some WiFi smartphones), and refuse to offer addresses to other (like my Ruckus R300 access points, other WiFi smartphones, etc.). In the logs the output seems to be exactly the same for working and non-working devices, and we got stuck. My last try was upgrade the Junos to last version, but only I got was th missing of the usual "show system services dhcp binding" command.
from your other post regarding vlan-trunks I can see you are using irb interfaces. The old DHCP daemon is not supported on irb-interfaces and you need to use JDHCP for proper operation - and I can see from the command you are trying to run, that you are using the old daemon.
the old daemon will be phased out - for now configuration works but you will get an error in 15.1X49-D60 stating that you should convert.