DualStack: Two VMs in the same network unable to communicate due to NPE after disabling SG on some ports

Setup:
Create a router and a network with IPv4 and IPv6 subnets.
Associate both the subnets to the router.

Spawn two VMs on the network and try to ping/ping6 from VM1 to VM2.
ping/ping6 is not working and the following exception is seen in Karaf.

java.lang.NullPointerException
at org.opendaylight.netvirt.aclservice.StatefulIngressAclServiceImpl.syncSpecificAclFlow(StatefulIngressAclServiceImpl.java:96)[371:org.opendaylight.netvirt.aclservice-impl:0.5.0.SNAPSHOT]
at org.opendaylight.netvirt.aclservice.AbstractIngressAclServiceImpl.programAceRule(AbstractIngressAclServiceImpl.java:225)[371:org.opendaylight.netvirt.aclservice-impl:0.5.0.SNAPSHOT]
at org.opendaylight.netvirt.aclservice.AbstractAclServiceImpl.syncRemoteAclRules(AbstractAclServiceImpl.java:209)[371:org.opendaylight.netvirt.aclservice-impl:0.5.0.SNAPSHOT]
at org.opendaylight.netvirt.aclservice.AbstractAclServiceImpl.updateCustomRules(AbstractAclServiceImpl.java:187)[371:org.opendaylight.netvirt.aclservice-impl:0.5.0.SNAPSHOT]
at org.opendaylight.netvirt.aclservice.AbstractAclServiceImpl.processInterfaceUpdate(AbstractAclServiceImpl.java:168)[371:org.opendaylight.netvirt.aclservice-impl:0.5.0.SNAPSHOT]
at org.opendaylight.netvirt.aclservice.AbstractAclServiceImpl.updateAcl(AbstractAclServiceImpl.java:138)[371:org.opendaylight.netvirt.aclservice-impl:0.5.0.SNAPSHOT]
at org.opendaylight.netvirt.aclservice.AclServiceManagerImpl.notify(AclServiceManagerImpl.java:57)[371:org.opendaylight.netvirt.aclservice-impl:0.5.0.SNAPSHOT]
at org.opendaylight.netvirt.aclservice.listeners.AclInterfaceListener.update(AclInterfaceListener.java:102)[371:org.opendaylight.netvirt.aclservice-impl:0.5.0.SNAPSHOT]
at org.opendaylight.netvirt.aclservice.listeners.AclInterfaceListener.update(AclInterfaceListener.java:33)[371:org.opendaylight.netvirt.aclservice-impl:0.5.0.SNAPSHOT]
at org.opendaylight.genius.datastoreutils.AsyncDataTreeChangeListenerBase$DataTreeChangeHandler.run(AsyncDataTreeChangeListenerBase.java:157)[320:org.opendaylight.genius.mdsalutil-api:0.3.0.SNAPSHOT]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)[:1.8.0_111]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)[:1.8.0_111]
at java.lang.Thread.run(Thread.java:745)[:1.8.0_111]

Looking at the OVS flows that are programmed on the switch, we could see that Table211 has only the drop rule and all packets (i.e., ping/ping6) are getting drop in this table.