Running a setup with 40 computes (not sure whether it is related or not), and for some reason the elan broadcast group (210001) is missing the qdhcp interface, and also missing the vxlan tunnel to the compute holding a VM connected to that network:

dump groups on the control/ODL node:
OFPST_GROUP_DESC reply (OF1.3) (xid=0x2):
group_id=200000,type=all,bucket=actions=set_field:00:1c:73:4e:d3:31->eth_dst,load:0x300->NXM_NX_REG6[],resubmit(,220)
group_id=210003,type=all
group_id=210004,type=all,bucket=actions=group:210003
group_id=150000,type=all,bucket=actions=set_field:fa:16:3e:c6:47:97->eth_dst,load:0x100->NXM_NX_REG6[],resubmit(,220)
group_id=210002,type=all,bucket=actions=group:210001
group_id=210001,type=all

dump groups on the compute node:
stack@nvp-scale-1-c6-bl-5-compute-1:~$ sudo ovs-ofctl -OOpenFlow13 dump-groups br-int | sort -n
group_id=150001,type=all,bucket=actions=set_field:fa:16:3e:69:8b:1a->eth_dst,load:0x2a00->NXM_NX_REG6[],resubmit(,220)
group_id=200000,type=all,bucket=actions=set_field:00:1c:73:4e:d3:31->eth_dst,load:0x2300->NXM_NX_REG6[],resubmit(,220)
group_id=200001,type=all
group_id=210001,type=all,bucket=actions=set_field:0x2a->tun_id,resubmit(,55)
group_id=210002,type=all,bucket=actions=group:210001,bucket=actions=set_field:0x1389->tun_id,output:3
group_id=210003,type=all
group_id=210004,type=all,bucket=actions=group:210003,bucket=actions=set_field:0x138a->tun_id,output:3

Attached several models outputs (ietf interface, elan, elaninterfaces) and ODL log