Forwarding rules apply with delay (UDP traffic) - sdn

Question

I am working on a project where Open vSwitch 2.9 (with kernel module 2.9) is installed on Ubuntu 16.04. I dynamically install forwarding rules for flows and remove them when the flow completes (using Floodlight controller 1.2). I am forwarding UDP traffic across VMs. My problem is that sometimes rules don't function.
For example, I see that a rule's packet counter increasing at one switch and on the next switch when I run tcpdump I see no packets coming in (although on the previous switch tcpdump shows packets on the correct outgoing interface). In some cases the forwarding suddenly starts working after a few minutes which is way too late!
Running netstat does not show any dropped UDP packets. I tried different versions of OVS and also tried using the userspace mode but the problem persists. I also noticed that depending on other flows that are installed, the switches where this problem occurs change but as long as I install all preceding flows the same way, the same switch and the same flow observes the problem. Any ideas what I might do next to figure out how to fix this?
Also, my forwarding rules use the following fields:
ovs0:~$ sudo ovs-ofctl dump-flows br0 -O OpenFlow13
cookie=0xafffff84962f92, duration=263.813s, table=0, n_packets=199405, n_bytes=269333926, send_flow_rem priority=12345,udp,in_port=eth2,nw_src=10.10.10.1,nw_d
st=10.10.10.2,tp_dst=3330 actions=output:eth3
cookie=0xafffff84962f95, duration=263.743s, table=0, n_packets=170236, n_bytes=229866720, send_flow_rem priority=12345,udp,in_port=eth3,nw_src=10.10.10.2,nw_d
st=10.10.10.1,tp_dst=1159 actions=output:eth2
cookie=0xafffff84962f9a, duration=263.437s, table=0, n_packets=202470, n_bytes=273485588, send_flow_rem priority=12345,udp,in_port=eth2,nw_src=10.10.10.1,nw_d
st=10.10.10.5,tp_dst=8450 actions=output:eth4
cookie=0xafffff84963066, duration=263.362s, table=0, n_packets=200642, n_bytes=271012852, send_flow_rem priority=12345,udp,in_port=eth4,nw_src=10.10.10.5,nw_d
st=10.10.10.1,tp_dst=9330 actions=output:eth2
cookie=0x0, duration=1294.627s, table=0, n_packets=447, n_bytes=381687, priority=0 actions=CONTROLLER:65535
I also tried using VLANs, same problem. This is the set of rules at the switch where packets are forwarded but not received at the next switch (flow with tp_dst=1966):
ovs7:~$ sudo ovs-ofctl dump-flows br0 -O OpenFlow13
cookie=0xafffff84963703, duration=158.640s, table=0, n_packets=75083, n_b
ytes=101947446, send_flow_rem priority=2,ip,in_port=eth5,dl_vlan=1895 acti
ons=pop_vlan,set_field:02:9b:dc:eb:80:c8->eth_dst,output:eth1
cookie=0xafffff8496e272, duration=93.641s, table=0, n_packets=3539, n_byt
es=4793142, send_flow_rem priority=2,ip,in_port=eth2,dl_vlan=1105 actions=
pop_vlan,set_field:02:9b:dc:eb:80:c8->eth_dst,output:eth1
cookie=0xafffff8496e419, duration=78.626s, table=0, n_packets=0, n_bytes=
0, send_flow_rem priority=2,ip,in_port=eth2,dl_vlan=1458 actions=output:et
h4
cookie=0xafffff8496de55, duration=148.614s, table=0, n_packets=66432, n_b
ytes=89933600, send_flow_rem priority=2,udp,in_port=eth1,nw_src=10.10.10.8
,nw_dst=10.10.10.12,tp_dst=1597 actions=push_vlan:0x8100,set_field:5693->v
lan_vid,output:eth5
cookie=0xafffff8496e0c9, duration=108.644s, table=0, n_packets=4592, n_by
tes=6203544, send_flow_rem priority=2,udp,in_port=eth1,nw_src=10.10.10.8,n
w_dst=10.10.10.12,tp_dst=1363 actions=push_vlan:0x8100,set_field:5459->vla
n_vid,output:eth4
*cookie=0xafffff8496e341, duration=83.644s, table=0, n_packets=3145, n_byt
es=4245630, send_flow_rem priority=2,udp,in_port=eth1,nw_src=10.10.10.8,nw
_dst=10.10.10.11,tp_dst=1966 actions=push_vlan:0x8100,set_field:6062->vlan
_vid,output:eth2*
cookie=0x0, duration=15540.491s, table=0, n_packets=683847, n_bytes=92457
8766, priority=0 actions=CONTROLLER:65535