If an entity is removed and new created within the same transaction the 'afterCompletition' procedure try to sync it twice.
It looks like that the entity is registered twice in this case.

The Exception is shown in the server.log, nevertheless the transactions and method execution will be succeed.
The following Exception can be safely ignored.

08:17:10,005 ERROR [org.jboss.as.ejb3] (EJB default - 4) JBAS014138: Exception releasing entity: java.lang.IllegalStateException: JBAS014172: Instance [org.jboss.as.cmp.component.CmpEntityBeanComponentInstance@31b489ae] not found in cache
at org.jboss.as.ejb3.component.entity.entitycache.ReferenceCountingEntityCache.release(ReferenceCountingEntityCache.java:86) [jboss-as-ejb3-7.2.0.Alpha1-SNAPSHOT.jar:7.2.0.Alpha1-SNAPSHOT]
at org.jboss.as.ejb3.component.entity.interceptors.EntityBeanSynchronizationInterceptor.releaseInstance(EntityBeanSynchronizationInterceptor.java:154) [jboss-as-ejb3-7.2.0.Alpha1-SNAPSHOT.jar:7.2.0.Alpha1-SNAPSHOT]
at org.jboss.as.ejb3.component.entity.interceptors.EntityBeanSynchronizationInterceptor.access$200(EntityBeanSynchronizationInterceptor.java:56) [jboss-as-ejb3-7.2.0.Alpha1-SNAPSHOT.jar:7.2.0.Alpha1-SNAPSHOT]
at org.jboss.as.ejb3.component.entity.interceptors.EntityBeanSynchronizationInterceptor$EntityBeanSynchronization.afterCompletion(EntityBeanSynchronizationInterceptor.java:219) [jboss-as-ejb3-7.2.0.Alpha1-SNAPSHOT.jar:7.2.0.Alpha1-SNAPSHOT]
at com.arjuna.ats.internal.jta.resources.arjunacore.SynchronizationImple.afterCompletion(SynchronizationImple.java:96)
at com.arjuna.ats.arjuna.coordinator.TwoPhaseCoordinator.afterCompletion(TwoPhaseCoordinator.java:402)
at com.arjuna.ats.arjuna.coordinator.TwoPhaseCoordinator.end(TwoPhaseCoordinator.java:103)
at com.arjuna.ats.arjuna.AtomicAction.commit(AtomicAction.java:162)
at com.arjuna.ats.internal.jta.transaction.arjunacore.TransactionImple.commitAndDisassociate(TransactionImple.java:1165)
at com.arjuna.ats.internal.jta.transaction.arjunacore.BaseTransaction.commit(BaseTransaction.java:126)
at com.arjuna.ats.jbossatx.BaseTransactionManagerDelegate.commit(BaseTransactionManagerDelegate.java:75)
at org.jboss.as.ejb3.tx.CMTTxInterceptor.endTransaction(CMTTxInterceptor.java:91) [jboss-as-ejb3-7.2.0.Alpha1-SNAPSHOT.jar:7.2.0.Alpha1-SNAPSHOT]
at org.jboss.as.ejb3.tx.CMTTxInterceptor.invokeInOurTx(CMTTxInterceptor.java:252) [jboss-as-ejb3-7.2.0.Alpha1-SNAPSHOT.jar:7.2.0.Alpha1-SNAPSHOT]
at org.jboss.as.ejb3.tx.CMTTxInterceptor.required(CMTTxInterceptor.java:315) [jboss-as-ejb3-7.2.0.Alpha1-SNAPSHOT.jar:7.2.0.Alpha1-SNAPSHOT]
at org.jboss.as.ejb3.tx.CMTTxInterceptor.processInvocation(CMTTxInterceptor.java:214) [jboss-as-ejb3-7.2.0.Alpha1-SNAPSHOT.jar:7.2.0.Alpha1-SNAPSHOT]
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288) [jboss-invocation-1.1.1.Final.jar:1.1.1.Final]
at org.jboss.as.ejb3.remote.EJBRemoteTransactionPropagatingInterceptor.processInvocation(EJBRemoteTransactionPropagatingInterceptor.java:79) [jboss-as-ejb3-7.2.0.Alpha1-SNAPSHOT.jar:7.2.0.Alpha1-SNAPSHOT]
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288) [jboss-invocation-1.1.1.Final.jar:1.1.1.Final]
at org.jboss.as.ejb3.component.interceptors.CurrentInvocationContextInterceptor.processInvocation(CurrentInvocationContextInterceptor.java:41) [jboss-as-ejb3-7.2.0.Alpha1-SNAPSHOT.jar:7.2.0.Alpha1-SNAPSHOT]
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288) [jboss-invocation-1.1.1.Final.jar:1.1.1.Final]
at org.jboss.as.ejb3.component.interceptors.ShutDownInterceptorFactory$1.processInvocation(ShutDownInterceptorFactory.java:64) [jboss-as-ejb3-7.2.0.Alpha1-SNAPSHOT.jar:7.2.0.Alpha1-SNAPSHOT]
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288) [jboss-invocation-1.1.1.Final.jar:1.1.1.Final]
at org.jboss.as.ejb3.component.interceptors.LoggingInterceptor.processInvocation(LoggingInterceptor.java:59) [jboss-as-ejb3-7.2.0.Alpha1-SNAPSHOT.jar:7.2.0.Alpha1-SNAPSHOT]
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288) [jboss-invocation-1.1.1.Final.jar:1.1.1.Final]
at org.jboss.as.ejb3.component.interceptors.EjbExceptionTransformingInterceptorFactories$1.processInvocation(EjbExceptionTransformingInterceptorFactories.java:65) [jboss-as-ejb3-7.2.0.Alpha1-SNAPSHOT.jar:7.2.0.Alpha1-SNAPSHOT]
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288) [jboss-invocation-1.1.1.Final.jar:1.1.1.Final]
at org.jboss.as.ee.component.NamespaceContextInterceptor.processInvocation(NamespaceContextInterceptor.java:50) [jboss-as-ee-7.2.0.Alpha1-SNAPSHOT.jar:7.2.0.Alpha1-SNAPSHOT]
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288) [jboss-invocation-1.1.1.Final.jar:1.1.1.Final]
at org.jboss.as.ejb3.component.interceptors.AdditionalSetupInterceptor.processInvocation(AdditionalSetupInterceptor.java:65) [jboss-as-ejb3-7.2.0.Alpha1-SNAPSHOT.jar:7.2.0.Alpha1-SNAPSHOT]
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288) [jboss-invocation-1.1.1.Final.jar:1.1.1.Final]
at org.jboss.as.ee.component.TCCLInterceptor.processInvocation(TCCLInterceptor.java:45) [jboss-as-ee-7.2.0.Alpha1-SNAPSHOT.jar:7.2.0.Alpha1-SNAPSHOT]
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288) [jboss-invocation-1.1.1.Final.jar:1.1.1.Final]
at org.jboss.invocation.ChainedInterceptor.processInvocation(ChainedInterceptor.java:61) [jboss-invocation-1.1.1.Final.jar:1.1.1.Final]
at org.jboss.as.ee.component.ViewService$View.invoke(ViewService.java:165) [jboss-as-ee-7.2.0.Alpha1-SNAPSHOT.jar:7.2.0.Alpha1-SNAPSHOT]
at org.jboss.as.ejb3.remote.protocol.versionone.MethodInvocationMessageHandler.invokeMethod(MethodInvocationMessageHandler.java:321) [jboss-as-ejb3-7.2.0.Alpha1-SNAPSHOT.jar:7.2.0.Alpha1-SNAPSHOT]
at org.jboss.as.ejb3.remote.protocol.versionone.MethodInvocationMessageHandler.access$100(MethodInvocationMessageHandler.java:69) [jboss-as-ejb3-7.2.0.Alpha1-SNAPSHOT.jar:7.2.0.Alpha1-SNAPSHOT]
at org.jboss.as.ejb3.remote.protocol.versionone.MethodInvocationMessageHandler$1.run(MethodInvocationMessageHandler.java:202) [jboss-as-ejb3-7.2.0.Alpha1-SNAPSHOT.jar:7.2.0.Alpha1-SNAPSHOT]
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471) [rt.jar:1.7.0_09-icedtea]
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334) [rt.jar:1.7.0_09-icedtea]
at java.util.concurrent.FutureTask.run(FutureTask.java:166) [rt.jar:1.7.0_09-icedtea]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110) [rt.jar:1.7.0_09-icedtea]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603) [rt.jar:1.7.0_09-icedtea]
at java.lang.Thread.run(Thread.java:722) [rt.jar:1.7.0_09-icedtea]
at org.jboss.threads.JBossThread.run(JBossThread.java:122)