[Bug]: Error: Client is not active

Describe the bug

This error appears from time to time: Error: Client is not active.
I attached logs from graylog, screenshot from ER, thread dump from the ITF Executor pod (on which this error appears)
There was no hazelcast restart for this period of time

To Reproduce

Version

version of ITF Executor: 4.4.357_opensource_20251023-070758

Logs

full_message
TcContext id 9176347988811276666, Project [..., ...], CallChain instance [9176347988811276665] '...', Step 'Step[9168426663511091168]': com.hazelcast.client.HazelcastClientNotActiveException: Client is not active.
at com.hazelcast.client.impl.clientside.HazelcastClientProxy.getClient(HazelcastClientProxy.java:303)
at com.hazelcast.client.impl.clientside.HazelcastClientProxy.getMap(HazelcastClientProxy.java:126)
at org.qubership.automation.itf.executor.cache.service.impl.PendingDataContextsCacheService.getPendingDataContexts(PendingDataContextsCacheService.java:75)
at org.qubership.automation.itf.executor.cache.service.impl.PendingDataContextsCacheService.getContextById(PendingDataContextsCacheService.java:60)
at org.qubership.automation.itf.executor.service.TCContextService.mergePendingContextsIfAny(TCContextService.java:335)
at org.qubership.automation.itf.core.instance.testcase.execution.subscriber.NextCallChainSubscriber.onEvent(NextCallChainSubscriber.java:131)
at org.qubership.automation.itf.core.instance.testcase.execution.subscriber.NextCallChainSubscriber.onEvent(NextCallChainSubscriber.java:65)
at org.qubership.automation.itf.core.instance.testcase.execution.subscriber.AbstractChainSubscriber.handleEvent(AbstractChainSubscriber.java:40)
at org.qubership.automation.itf.core.instance.testcase.execution.subscriber.NextCallChainSubscriber.handle(NextCallChainSubscriber.java:94)
at sun.reflect.GeneratedMethodAccessor530.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at com.google.common.eventbus.Subscriber.invokeSubscriberMethod(Subscriber.java:85)
at com.google.common.eventbus.Subscriber.lambda$dispatchEvent$0(Subscriber.java:71)
at com.google.common.util.concurrent.DirectExecutor.execute(DirectExecutor.java:31)
at com.google.common.eventbus.Subscriber.dispatchEvent(Subscriber.java:68)
at com.google.common.eventbus.Dispatcher$PerThreadQueuedDispatcher.dispatch(Dispatcher.java:109)
at com.google.common.eventbus.EventBus.post(EventBus.java:270)
at org.qubership.automation.itf.executor.provider.EventBusProvider.post(EventBusProvider.java:49)
at org.qubership.automation.itf.core.instance.testcase.chain.CallChainExecutorService._executeInstance(CallChainExecutorService.java:132)
at org.qubership.automation.itf.core.instance.testcase.chain.CallChainExecutorService.lambda$execute$1(CallChainExecutorService.java:309)
at org.qubership.automation.itf.core.util.db.TxExecutor.execute(TxExecutor.java:140)
at org.qubership.automation.itf.core.instance.testcase.chain.CallChainExecutorService.execute(CallChainExecutorService.java:307)
at org.qubership.automation.itf.core.instance.testcase.chain.CallChainExecutorService.lambda$executeInstance$0(CallChainExecutorService.java:264)
at org.qubership.automation.itf.core.execution.WaitTimeMonitoringThreadPoolExecutor.lambda$submit$1(WaitTimeMonitoringThreadPoolExecutor.java:72)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
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:750)

Additional information

thread dump:
atp-itf-executor-9f79f5b77-vgb5r__td_pid29.log

Start with the attached Graylog logs and thread dump, then trace PendingDataContextsCacheService.java at getPendingDataContexts and TCContextService.java at mergePendingContextsIfAny. Determine why the Hazelcast client becomes inactive without a reported restart and define a reproducible failure case. Done means the intermittent exception is explained and the executor handles the condition without losing the pending context.