IdStory Identity Manager

version 9.6.5
When I generated a report "provisioning-operation-report" this error occured:

java.lang.ClassNotFoundException: provisioning-operation-report
    at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1309)
    at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1137)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:264)
    at eu.bcvsolutions.idm.core.scheduler.service.impl.DefaultLongRunningTaskManager.createTaskExecutor(DefaultLongRunningTaskManager.java:472)
    at eu.bcvsolutions.idm.core.scheduler.service.impl.DefaultLongRunningTaskManager.processCreated(DefaultLongRunningTaskManager.java:154)
    at eu.bcvsolutions.idm.core.scheduler.service.impl.DefaultLongRunningTaskManager.lambda$processCreated$288(DefaultLongRunningTaskManager.java:133)
    at java.util.ArrayList.forEach(ArrayList.java:1257)
    at eu.bcvsolutions.idm.core.scheduler.service.impl.DefaultLongRunningTaskManager.processCreated(DefaultLongRunningTaskManager.java:132)
    at eu.bcvsolutions.idm.core.scheduler.service.impl.DefaultLongRunningTaskManager.scheduleProcessCreated(DefaultLongRunningTaskManager.java:117)
    at eu.bcvsolutions.idm.core.scheduler.service.impl.DefaultLongRunningTaskManager$$FastClassBySpringCGLIB$$3b41f3cc.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.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:99)
    at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:281)
    at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
    at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:655)
    at eu.bcvsolutions.idm.core.scheduler.service.impl.DefaultLongRunningTaskManager$$EnhancerBySpringCGLIB$$fcd29470.scheduleProcessCreated(<generated>)
    at sun.reflect.GeneratedMethodAccessor475.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.springframework.scheduling.support.ScheduledMethodRunnable.run(ScheduledMethodRunnable.java:65)
    at org.springframework.scheduling.support.DelegatingErrorHandlingRunnable.run(DelegatingErrorHandlingRunnable.java:54)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
    at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308)
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180)
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294)
    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)

I tried to generate it again for the same system after about 50 second and the report has been generated without any error.