Shards fail to settle after brief isolation

This is different from other isolation Bugs in that no major timeout is hit before bad things start to happen. This is also similar to CONTROLLER-1684 in that OutOfOrderRequestException is visible from Robot.

The scenario is using module-based shards with tell-based protocol, transaction producer on each member and short isolation on the original leader (member-1).
The first suspicious messages in karaf.log [0] are the repeated:
2017-05-17 13:28:51,032 | INFO | lt-dispatcher-22 | Shard | 192 - org.opendaylight.controller.sal-clustering-commons - 1.5.0.Carbon | member-1-shard-default-config (Follower): The prevLogIndex 33 was found in the log but the term -1 is not equal to the append entriesprevLogTerm 2 - lastIndex: 36, snapshotIndex: 34
2017-05-17 13:28:51,032 | INFO | lt-dispatcher-22 | Shard | 192 - org.opendaylight.controller.sal-clustering-commons - 1.5.0.Carbon | member-1-shard-default-config (Follower): Follower is out-of-sync so sending negative reply: AppendEntriesReply [term=4, success=false, followerId=member-1-shard-default-config, logLastIndex=36, logLastTerm=2, forceInstallSnapshot=false, payloadVersion=5, raftVersion=3]

Robot has gathered failure responses [1] from each member, member-1 sent NullPointerException according to karaf.log:
2017-05-17 13:29:42,277 | WARN | lt-dispatcher-25 | ConcurrentDOMDataBroker | 199 - org.opendaylight.controller.sal-distributed-datastore - 1.5.0.Carbon | Tx: DOM-CHAIN-1-2 Error during phase CAN_COMMIT, starting Abort
java.lang.NullPointerException
at org.opendaylight.controller.cluster.datastore.FrontendReadWriteTransaction.ensureReady(FrontendReadWriteTransaction.java:336)
at org.opendaylight.controller.cluster.datastore.FrontendReadWriteTransaction.handleModifyTransaction(FrontendReadWriteTransaction.java:319)
at org.opendaylight.controller.cluster.datastore.FrontendReadWriteTransaction.handleRequest(FrontendReadWriteTransaction.java:90)
at org.opendaylight.controller.cluster.datastore.AbstractFrontendHistory.handleTransactionRequest(AbstractFrontendHistory.java:154)
at org.opendaylight.controller.cluster.datastore.LeaderFrontendState.handleTransactionRequest(LeaderFrontendState.java:198)
at org.opendaylight.controller.cluster.datastore.Shard.handleRequest(Shard.java:461)
at org.opendaylight.controller.cluster.datastore.Shard.handleNonRaftCommand(Shard.java:292)
at org.opendaylight.controller.cluster.raft.RaftActor.handleCommand(RaftActor.java:270)

[0] https://logs.opendaylight.org/releng/jenkins092/controller-csit-3node-clustering-only-carbon/693/archives/odl1_karaf.log.gz
[1] https://logs.opendaylight.org/releng/jenkins092/controller-csit-3node-clustering-only-carbon/693/archives/log.html.gz#s1-s28-t1-k2-k23-k1-k1