502 Bad Gateway when logging out

When users log out or are in an idle session they get the page “502 Bad Gateway”

In the logfile i can see following:

2021-09-07 21:34:42,514 ERROR [org.keycloak.services.error.KeycloakErrorHandler] (default task-5942) Uncaught server error: java.lang.IllegalStateException: Can't add session: task in progress for session
        at org.keycloak.keycloak-model-infinispan@11.0.3//org.keycloak.models.sessions.infinispan.InfinispanKeycloakTransaction.put(InfinispanKeycloakTransaction.java:84)
        at org.keycloak.keycloak-model-infinispan@11.0.3//org.keycloak.models.sessions.infinispan.InfinispanAuthenticationSessionProvider.createRootAuthenticationSession(InfinispanAuthenticationSessionProvider.java:83)
        at org.keycloak.keycloak-services@11.0.3//org.keycloak.services.managers.AuthenticationManager.createOrJoinLogoutSession(AuthenticationManager.java:290)
        at org.keycloak.keycloak-services@11.0.3//org.keycloak.services.managers.AuthenticationManager.browserLogout(AuthenticationManager.java:529)
        at org.keycloak.keycloak-services@11.0.3//org.keycloak.protocol.oidc.endpoints.LogoutEndpoint.initiateBrowserLogout(LogoutEndpoint.java:270)
        at org.keycloak.keycloak-services@11.0.3//org.keycloak.protocol.oidc.endpoints.LogoutEndpoint.logout(LogoutEndpoint.java:151)
        at jdk.internal.reflect.GeneratedMethodAccessor784.invoke(Unknown Source)
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.base/java.lang.reflect.Method.invoke(Method.java:566)
        at org.jboss.resteasy.resteasy-jaxrs@3.12.1.Final//org.jboss.resteasy.core.MethodInjectorImpl.invoke(MethodInjectorImpl.java:138)
        at org.jboss.resteasy.resteasy-jaxrs@3.12.1.Final//org.jboss.resteasy.core.ResourceMethodInvoker.internalInvokeOnTarget(ResourceMethodInvoker.java:543)
        at org.jboss.resteasy.resteasy-jaxrs@3.12.1.Final//org.jboss.resteasy.core.ResourceMethodInvoker.invokeOnTargetAfterFilter(ResourceMethodInvoker.java:432)
        at org.jboss.resteasy.resteasy-jaxrs@3.12.1.Final//org.jboss.resteasy.core.ResourceMethodInvoker.lambda$invokeOnTarget$0(ResourceMethodInvoker.java:393)
        at org.jboss.resteasy.resteasy-jaxrs@3.12.1.Final//org.jboss.resteasy.core.interception.PreMatchContainerRequestContext.filter(PreMatchContainerRequestContext.java:358)
        at org.jboss.resteasy.resteasy-jaxrs@3.12.1.Final//org.jboss.resteasy.core.ResourceMethodInvoker.invokeOnTarget(ResourceMethodInvoker.java:395)
        at org.jboss.resteasy.resteasy-jaxrs@3.12.1.Final//org.jboss.resteasy.core.ResourceMethodInvoker.invoke(ResourceMethodInvoker.java:364)
        at org.jboss.resteasy.resteasy-jaxrs@3.12.1.Final//org.jboss.resteasy.core.ResourceLocatorInvoker.invokeOnTargetObject(ResourceLocatorInvoker.java:150)
        at org.jboss.resteasy.resteasy-jaxrs@3.12.1.Final//org.jboss.resteasy.core.ResourceLocatorInvoker.invoke(ResourceLocatorInvoker.java:110)
        at org.jboss.resteasy.resteasy-jaxrs@3.12.1.Final//org.jboss.resteasy.core.ResourceLocatorInvoker.invokeOnTargetObject(ResourceLocatorInvoker.java:141)
        at org.jboss.resteasy.resteasy-jaxrs@3.12.1.Final//org.jboss.resteasy.core.ResourceLocatorInvoker.invoke(ResourceLocatorInvoker.java:104)
        at org.jboss.resteasy.resteasy-jaxrs@3.12.1.Final//org.jboss.resteasy.core.SynchronousDispatcher.invoke(SynchronousDispatcher.java:440)
        at org.jboss.resteasy.resteasy-jaxrs@3.12.1.Final//org.jboss.resteasy.core.SynchronousDispatcher.lambda$invoke$4(SynchronousDispatcher.java:229)
        at org.jboss.resteasy.resteasy-jaxrs@3.12.1.Final//org.jboss.resteasy.core.SynchronousDispatcher.lambda$preprocess$0(SynchronousDispatcher.java:135)
        at org.jboss.resteasy.resteasy-jaxrs@3.12.1.Final//org.jboss.resteasy.core.interception.PreMatchContainerRequestContext.filter(PreMatchContainerRequestContext.java:358)
        at org.jboss.resteasy.resteasy-jaxrs@3.12.1.Final//org.jboss.resteasy.core.SynchronousDispatcher.preprocess(SynchronousDispatcher.java:138)
        at org.jboss.resteasy.resteasy-jaxrs@3.12.1.Final//org.jboss.resteasy.core.SynchronousDispatcher.invoke(SynchronousDispatcher.java:215)
        at org.jboss.resteasy.resteasy-jaxrs@3.12.1.Final//org.jboss.resteasy.plugins.server.servlet.ServletContainerDispatcher.service(ServletContainerDispatcher.java:245)
        at org.jboss.resteasy.resteasy-jaxrs@3.12.1.Final//org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher.service(HttpServletDispatcher.java:61)
        at org.jboss.resteasy.resteasy-jaxrs@3.12.1.Final//org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher.service(HttpServletDispatcher.java:56)
        at javax.servlet.api@2.0.0.Final//javax.servlet.http.HttpServlet.service(HttpServlet.java:590)
        at io.undertow.servlet@2.1.3.Final//io.undertow.servlet.handlers.ServletHandler.handleRequest(ServletHandler.java:74)
        at io.undertow.servlet@2.1.3.Final//io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:129)
        at org.keycloak.keycloak-wildfly-extensions@11.0.3//org.keycloak.provider.wildfly.WildFlyRequestFilter.lambda$doFilter$0(WildFlyRequestFilter.java:41)
        at org.keycloak.keycloak-services@11.0.3//org.keycloak.services.filters.AbstractRequestFilter.filter(AbstractRequestFilter.java:43)
        at org.keycloak.keycloak-wildfly-extensions@11.0.3//org.keycloak.provider.wildfly.WildFlyRequestFilter.doFilter(WildFlyRequestFilter.java:39)
        at io.undertow.servlet@2.1.3.Final//io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61)
        at io.undertow.servlet@2.1.3.Final//io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131)
        at io.undertow.servlet@2.1.3.Final//io.undertow.servlet.handlers.FilterHandler.handleRequest(FilterHandler.java:84)
        at io.undertow.servlet@2.1.3.Final//io.undertow.servlet.handlers.security.ServletSecurityRoleHandler.handleRequest(ServletSecurityRoleHandler.java:62)
        at io.undertow.servlet@2.1.3.Final//io.undertow.servlet.handlers.ServletChain$1.handleRequest(ServletChain.java:68)
        at io.undertow.servlet@2.1.3.Final//io.undertow.servlet.handlers.ServletDispatchingHandler.handleRequest(ServletDispatchingHandler.java:36)
        at org.wildfly.extension.undertow@20.0.1.Final//org.wildfly.extension.undertow.security.SecurityContextAssociationHandler.handleRequest(SecurityContextAssociationHandler.java:78)
        at io.undertow.core@2.1.3.Final//io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
        at io.undertow.servlet@2.1.3.Final//io.undertow.servlet.handlers.RedirectDirHandler.handleRequest(RedirectDirHandler.java:68)
        at io.undertow.servlet@2.1.3.Final//io.undertow.servlet.handlers.security.SSLInformationAssociationHandler.handleRequest(SSLInformationAssociationHandler.java:132)
        at io.undertow.servlet@2.1.3.Final//io.undertow.servlet.handlers.security.ServletAuthenticationCallHandler.handleRequest(ServletAuthenticationCallHandler.java:57)
        at io.undertow.core@2.1.3.Final//io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
        at io.undertow.core@2.1.3.Final//io.undertow.security.handlers.AbstractConfidentialityHandler.handleRequest(AbstractConfidentialityHandler.java:46)
        at io.undertow.servlet@2.1.3.Final//io.undertow.servlet.handlers.security.ServletConfidentialityConstraintHandler.handleRequest(ServletConfidentialityConstraintHandler.java:64)
        at io.undertow.core@2.1.3.Final//io.undertow.security.handlers.AuthenticationMechanismsHandler.handleRequest(AuthenticationMechanismsHandler.java:60)
        at io.undertow.servlet@2.1.3.Final//io.undertow.servlet.handlers.security.CachedAuthenticatedSessionHandler.handleRequest(CachedAuthenticatedSessionHandler.java:77)
        at io.undertow.core@2.1.3.Final//io.undertow.security.handlers.NotificationReceiverHandler.handleRequest(NotificationReceiverHandler.java:50)
        at io.undertow.core@2.1.3.Final//io.undertow.security.handlers.AbstractSecurityContextAssociationHandler.handleRequest(AbstractSecurityContextAssociationHandler.java:43)
        at io.undertow.core@2.1.3.Final//io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
        at org.wildfly.extension.undertow@20.0.1.Final//org.wildfly.extension.undertow.security.jacc.JACCContextIdHandler.handleRequest(JACCContextIdHandler.java:61)
        at io.undertow.core@2.1.3.Final//io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
        at org.wildfly.extension.undertow@20.0.1.Final//org.wildfly.extension.undertow.deployment.GlobalRequestControllerHandler.handleRequest(GlobalRequestControllerHandler.java:68)
        at io.undertow.core@2.1.3.Final//io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
        at io.undertow.servlet@2.1.3.Final//io.undertow.servlet.handlers.ServletInitialHandler.handleFirstRequest(ServletInitialHandler.java:269)
        at io.undertow.servlet@2.1.3.Final//io.undertow.servlet.handlers.ServletInitialHandler.access$100(ServletInitialHandler.java:78)
        at io.undertow.servlet@2.1.3.Final//io.undertow.servlet.handlers.ServletInitialHandler$2.call(ServletInitialHandler.java:133)
        at io.undertow.servlet@2.1.3.Final//io.undertow.servlet.handlers.ServletInitialHandler$2.call(ServletInitialHandler.java:130)
        at io.undertow.servlet@2.1.3.Final//io.undertow.servlet.core.ServletRequestContextThreadSetupAction$1.call(ServletRequestContextThreadSetupAction.java:48)
        at io.undertow.servlet@2.1.3.Final//io.undertow.servlet.core.ContextClassLoaderSetupAction$1.call(ContextClassLoaderSetupAction.java:43)
        at org.wildfly.extension.undertow@20.0.1.Final//org.wildfly.extension.undertow.security.SecurityContextThreadSetupAction.lambda$create$0(SecurityContextThreadSetupAction.java:105)
        at org.wildfly.extension.undertow@20.0.1.Final//org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1530)
        at org.wildfly.extension.undertow@20.0.1.Final//org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1530)
        at org.wildfly.extension.undertow@20.0.1.Final//org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1530)
        at org.wildfly.extension.undertow@20.0.1.Final//org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1530)
        at io.undertow.servlet@2.1.3.Final//io.undertow.servlet.handlers.ServletInitialHandler.dispatchRequest(ServletInitialHandler.java:249)
        at io.undertow.servlet@2.1.3.Final//io.undertow.servlet.handlers.ServletInitialHandler.access$000(ServletInitialHandler.java:78)
        at io.undertow.servlet@2.1.3.Final//io.undertow.servlet.handlers.ServletInitialHandler$1.handleRequest(ServletInitialHandler.java:99)
        at io.undertow.core@2.1.3.Final//io.undertow.server.Connectors.executeRootHandler(Connectors.java:370)
        at io.undertow.core@2.1.3.Final//io.undertow.server.HttpServerExchange$1.run(HttpServerExchange.java:830)
        at org.jboss.threads@2.3.3.Final//org.jboss.threads.ContextClassLoaderSavingRunnable.run(ContextClassLoaderSavingRunnable.java:35)
        at org.jboss.threads@2.3.3.Final//org.jboss.threads.EnhancedQueueExecutor.safeRun(EnhancedQueueExecutor.java:1982)
        at org.jboss.threads@2.3.3.Final//org.jboss.threads.EnhancedQueueExecutor$ThreadBody.doRunTask(EnhancedQueueExecutor.java:1486)
        at org.jboss.threads@2.3.3.Final//org.jboss.threads.EnhancedQueueExecutor$ThreadBody.run(EnhancedQueueExecutor.java:1377)
        at java.base/java.lang.Thread.run(Thread.java:834)

Can anyone assist with this?
Thanks in advance.