NPE when used Timers with temporal operators in the LHS pattern

NPE when used Timers with temporal operators. When the rule is invalidated by the clock we see:

Unable to execute timer job!
java.lang.NullPointerException
at org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:1236)
at org.drools.common.Scheduler$ActivationTimerJob.execute(Scheduler.java:91)
at org.drools.time.SelfRemovalJob.execute(SelfRemovalJob.java:15)
at org.drools.time.impl.DefaultTimerJobInstance.call(DefaultTimerJobInstance.java:47)
at org.drools.time.impl.DefaultTimerJobInstance.call(DefaultTimerJobInstance.java:12)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
at java.util.concurrent.FutureTask.run(FutureTask.java:138)

Unit test attached.