I have a similar problem on 15.1X49-D70. Only some DHCP requests are replied (after a while) some not.
The old ssg140 firewall is working fine in the same position.
admin@srx# run show dhcp server binding
IP address Session Id Hardware address Expires State Interface
192.168.0.198 6 00:61:71:e2:00:00 85024 BOUND ge-0/0/6.0
192.168.0.193 1 64:66:b3:c7:00:00 84460 SELECTING ge-0/0/6.0
192.168.0.211 19 68:05:ca:30:00:00 86395 SELECTING ge-0/0/6.0
192.168.0.199 7 9c:f3:87:33:00:00 84914 BOUND ge-0/0/6.0
192.168.0.196 4 a4:67:06:68:00:00 84496 BOUND ge-0/0/6.0
192.168.0.202 10 c8:bc:c8:ee:00:00 84807 BOUND ge-0/0/6.0
192.168.0.197 5 cc:44:63:d1:00:00 84500 BOUND ge-0/0/6.0
192.168.0.212 20 d0:50:99:47:00:00 86398 SELECTING ge-0/0/6.0
192.168.0.195 3 e8:94:f6:33:00:00 84463 SELECTING ge-0/0/6.0
192.168.0.194 2 e8:94:f6:3f:00:00 84461 SELECTING ge-0/0/6.0
Debugs are not available:
admin@srx# show system services dhcp-local-server
##
## Warning: configuration block ignored: unsupported platform (srx340)
##
traceoptions { ## Warning: 'traceoptions' is deprecated
file dhcp.log;
flag all;
}
Alf