Copycat exception: Log index out of bounds

Exception stack trace.

2015-12-10 12:13:50,581 | DEBUG | copycat-p2-1 | FollowerState | 71 - org.onosproject.onlab-thirdparty - 1.4.0.SNAPSHOT | onos://10.128.12.1:9876 - Reset heartbeat timeout
2015-12-10 12:13:50,581 | DEBUG | copycat-p2-1 | FollowerState | 71 - org.onosproject.onlab-thirdparty - 1.4.0.SNAPSHOT | onos://10.128.12.1:9876 - Received AppendRequest[term=3, leader=onos://10.128.12.2:9876, logIndex=null, logTerm=null, entries=[3], firstIndex=true, commitIndex=3]
2015-12-10 12:13:50,581 | WARN | copycat-p2-1 | FollowerState | 71 - org.onosproject.onlab-thirdparty - 1.4.0.SNAPSHOT | onos://10.128.12.1:9876 - Synced entry does not match local log, removing incorrect entries
2015-12-10 12:13:50,581 | WARN | copycat-p2-1 | FollowerState | 71 - org.onosproject.onlab-thirdparty - 1.4.0.SNAPSHOT | doAppendEntries
java.lang.IndexOutOfBoundsException: Log index out of bounds
at net.kuujo.copycat.util.internal.Assert.index(Assert.java:114)[71:org.onosproject.onlab-thirdparty:1.4.0.SNAPSHOT]
at net.kuujo.copycat.state.internal.SnapshottableLogManager.removeAfter(SnapshottableLogManager.java:190)[71:org.onosproject.onlab-thirdparty:1.4.0.SNAPSHOT]
at net.kuujo.copycat.raft.ActiveState.doAppendEntries(ActiveState.java:195)[71:org.onosproject.onlab-thirdparty:1.4.0.SNAPSHOT]
at net.kuujo.copycat.raft.ActiveState.handleAppend(ActiveState.java:86)[71:org.onosproject.onlab-thirdparty:1.4.0.SNAPSHOT]
at net.kuujo.copycat.raft.ActiveState.append(ActiveState.java:49)[71:org.onosproject.onlab-thirdparty:1.4.0.SNAPSHOT]
at net.kuujo.copycat.raft.FollowerState.append(FollowerState.java:157)
at net.kuujo.copycat.raft.RaftContext.lambda$wrapCall$21(RaftContext.java:562)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)[:1.8.0_66]
at java.util.concurrent.FutureTask.run(FutureTask.java:266)[:1.8.0_66]
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:180)[:1.8.0_66]
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:293)[:1.8.0_66]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)[:1.8.0_66]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)[:1.8.0_66]
at java.lang.Thread.run(Thread.java:745)[:1.8.0_66]