IdStory Identity Manager

I am running IdM with this configuration:

...
scheduler.task.executor.corePoolSize=2
scheduler.task.executor.maxPoolSize=10
scheduler.task.executor.queueCapacity=2
...

When I create more than 2 LRTs, the pool is expanded and additional LRTs become Running.
When I create more than maxPoolSize LRTs, all LRTs are enqueued. LRTs that were created after the number of LRTs reached maxPoolSize seem to be correct. However, when they are about to run, they enter the Failed state with following error:

java.lang.IllegalArgumentException: [Assertion failed] - this argument is required; it must not be null
    at org.springframework.util.Assert.notNull(Assert.java:115)
    at org.springframework.util.Assert.notNull(Assert.java:126)
    at eu.bcvsolutions.idm.core.api.bulk.action.AbstractBulkAction.process(AbstractBulkAction.java:172)
    at eu.bcvsolutions.idm.core.api.bulk.action.AbstractBulkAction.process(AbstractBulkAction.java:47)
    at eu.bcvsolutions.idm.core.scheduler.api.service.AbstractLongRunningTaskExecutor.call(AbstractLongRunningTaskExecutor.java:197)
    at eu.bcvsolutions.idm.core.scheduler.api.service.AbstractLongRunningTaskExecutor$$FastClassBySpringCGLIB$$f9eae371.invoke(<generated>)
    at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204)
    at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:720)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157)
    at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
    at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:655)
    at eu.bcvsolutions.idm.acc.bulk.action.impl.IdentityAccountManagementBulkAction$$EnhancerBySpringCGLIB$$f9ddabf2.call(<generated>)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at org.springframework.security.concurrent.DelegatingSecurityContextRunnable.run(DelegatingSecurityContextRunnable.java:80)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at java.lang.Thread.run(Thread.java:748)

This is because a rejection policy on the task queue is not implemented yet.