undefine connectors attribute of broadcast-group throws IllegalArgumentException

/profile=full-ha/subsystem=messaging-activemq/server=default/broadcast-group=bg-group1:undefine-attribute(name=connectors)
{
    "outcome" => "failed",
    "failure-description" => {"domain-failure-description" => "WFLYCTL0158: Operation handler failed: java.lang.IllegalArgumentException"},
    "rolled-back" => true
}

2018-04-16 15:41:16,830 ERROR [org.jboss.as.controller.management-operation] (management-handler-thread - 2) WFLYCTL0013: Operation ("undefine-attribute") failed - address: ([
    ("profile" => "full-ha"),
    ("subsystem" => "messaging-activemq"),
    ("server" => "default"),
    ("broadcast-group" => "bg-group1")
]): java.lang.IllegalArgumentException
        at org.jboss.dmr.ModelValue.asList(ModelValue.java:143)
        at org.jboss.dmr.ModelNode.asList(ModelNode.java:1592)
        at org.wildfly.extension.messaging.activemq.BroadcastGroupDefinition.validateConnectors(BroadcastGroupDefinition.java:149)
        at org.wildfly.extension.messaging.activemq.BroadcastGroupWriteAttributeHandler.finishModelStage(BroadcastGroupWriteAttributeHandler.java:47)
        at org.jboss.as.controller.AbstractWriteAttributeHandler.execute(AbstractWriteAttributeHandler.java:95)
        at org.jboss.as.controller.operations.global.WriteAttributeHandler.doExecuteInternal(WriteAttributeHandler.java:194)
        at org.jboss.as.controller.operations.global.WriteAttributeHandler.execute(WriteAttributeHandler.java:115)
        at org.jboss.as.controller.operations.global.UndefineAttributeHandler.execute(UndefineAttributeHandler.java:52)
        at org.jboss.as.controller.AbstractOperationContext.executeStep(AbstractOperationContext.java:982)
        at org.jboss.as.controller.AbstractOperationContext.processStages(AbstractOperationContext.java:726)
        at org.jboss.as.controller.AbstractOperationContext.executeOperation(AbstractOperationContext.java:450)
        at org.jboss.as.controller.OperationContextImpl.executeOperation(OperationContextImpl.java:1408)
        at org.jboss.as.controller.ModelControllerImpl.internalExecute(ModelControllerImpl.java:423)
        at org.jboss.as.controller.ModelControllerImpl.lambda$execute$1(ModelControllerImpl.java:243)
        at org.wildfly.security.auth.server.SecurityIdentity.runAs(SecurityIdentity.java:263)
        at org.wildfly.security.auth.server.SecurityIdentity.runAs(SecurityIdentity.java:229)
        at org.jboss.as.controller.ModelControllerImpl.execute(ModelControllerImpl.java:243)
        at org.jboss.as.controller.remote.ModelControllerClientOperationHandler$ExecuteRequestHandler.doExecute(ModelControllerClientOperationHandler.java:240)
        at org.jboss.as.controller.remote.ModelControllerClientOperationHandler$ExecuteRequestHandler.access$400(ModelControllerClientOperationHandler.java:138)
        at org.jboss.as.controller.remote.ModelControllerClientOperationHandler$ExecuteRequestHandler$1$1.run(ModelControllerClientOperationHandler.java:162)
        at org.jboss.as.controller.remote.ModelControllerClientOperationHandler$ExecuteRequestHandler$1$1.run(ModelControllerClientOperationHandler.java:158)
        at org.wildfly.security.auth.server.SecurityIdentity.runAs(SecurityIdentity.java:287)
        at org.wildfly.security.auth.server.SecurityIdentity.runAs(SecurityIdentity.java:244)
        at org.jboss.as.controller.AccessAuditContext.doAs(AccessAuditContext.java:254)
        at org.jboss.as.controller.AccessAuditContext.doAs(AccessAuditContext.java:225)
        at org.jboss.as.controller.remote.ModelControllerClientOperationHandler$ExecuteRequestHandler$1.execute(ModelControllerClientOperationHandler.java:158)
        at org.jboss.as.protocol.mgmt.ManagementRequestContextImpl$1.doExecute(ManagementRequestContextImpl.java:70)
        at org.jboss.as.protocol.mgmt.ManagementRequestContextImpl$AsyncTaskRunner.run(ManagementRequestContextImpl.java:160)
        at org.jboss.threads.ContextClassLoaderSavingRunnable.run(ContextClassLoaderSavingRunnable.java:35)
        at org.jboss.threads.EnhancedQueueExecutor.safeRun(EnhancedQueueExecutor.java:1985)
        at org.jboss.threads.EnhancedQueueExecutor$ThreadBody.doRunTask(EnhancedQueueExecutor.java:1487)
        at org.jboss.threads.EnhancedQueueExecutor$ThreadBody.run(EnhancedQueueExecutor.java:1378)
        at java.lang.Thread.run(Thread.java:748)
        at org.jboss.threads.JBossThread.run(JBossThread.java:485)