NPE in ChannelMetric for non-master nodes

Attempting to retrieve the jgroups subsystem attributes of a non-master node on a RELAY channel causes an NPE.

[Server:earth-one] 18:36:34,055 ERROR [org.jboss.as.controller.management-operation] (ServerService Thread Pool – 35) WFLYCTL0013: Operation ("read-attribute") failed - address: ([
[Server:earth-one] ("subsystem" => "datagrid-jgroups"),
[Server:earth-one] ("channel" => "xsite")
[Server:earth-one] ]): java.lang.IllegalArgumentException: value is null
[Server:earth-one] at org.jboss.dmr.ModelNode.<init>(ModelNode.java:162)
[Server:earth-one] at org.infinispan.server.jgroups.subsystem.ChannelMetric$2.execute(ChannelMetric.java:46)
[Server:earth-one] at org.infinispan.server.jgroups.subsystem.ChannelMetric$2.execute(ChannelMetric.java:43)
[Server:earth-one] at org.infinispan.server.jgroups.subsystem.ChannelMetricExecutor.execute(ChannelMetricExecutor.java:47)
[Server:earth-one] at org.infinispan.server.commons.controller.MetricHandler.executeRuntimeStep(MetricHandler.java:70)
[Server:earth-one] at org.jboss.as.controller.AbstractRuntimeOnlyHandler$1.execute(AbstractRuntimeOnlyHandler.java:53)
[Server:earth-one] at org.jboss.as.controller.AbstractOperationContext.executeStep(AbstractOperationContext.java:890)
[Server:earth-one] at org.jboss.as.controller.AbstractOperationContext.processStages(AbstractOperationContext.java:659)
[Server:earth-one] at org.jboss.as.controller.AbstractOperationContext.executeOperation(AbstractOperationContext.java:370)
[Server:earth-one] at org.jboss.as.controller.OperationContextImpl.executeOperation(OperationContextImpl.java:1344)
[Server:earth-one] at org.jboss.as.controller.ModelControllerImpl.internalExecute(ModelControllerImpl.java:392)
[Server:earth-one] at org.jboss.as.controller.ModelControllerImpl.execute(ModelControllerImpl.java:217)
[Server:earth-one] at org.jboss.as.controller.remote.TransactionalProtocolOperationHandler.internalExecute(TransactionalProtocolOperationHandler.java:247)
[Server:earth-one] at org.jboss.as.controller.remote.TransactionalProtocolOperationHandler$ExecuteRequestHandler.doExecute(TransactionalProtocolOperationHandler.java:185)
[Server:earth-one] at org.jboss.as.controller.remote.TransactionalProtocolOperationHandler$ExecuteRequestHandler$1.run(TransactionalProtocolOperationHandler.java:138)
[Server:earth-one] at org.jboss.as.controller.remote.TransactionalProtocolOperationHandler$ExecuteRequestHandler$1.run(TransactionalProtocolOperationHandler.java:134)
[Server:earth-one] at java.security.AccessController.doPrivileged(Native Method)
[Server:earth-one] at javax.security.auth.Subject.doAs(Subject.java:360)
[Server:earth-one] at org.jboss.as.controller.AccessAuditContext.doAs(AccessAuditContext.java:81)
[Server:earth-one] at org.jboss.as.controller.remote.TransactionalProtocolOperationHandler$ExecuteRequestHandler$2$1.run(TransactionalProtocolOperationHandler.java:157)
[Server:earth-one] at org.jboss.as.controller.remote.TransactionalProtocolOperationHandler$ExecuteRequestHandler$2$1.run(TransactionalProtocolOperationHandler.java:153)
[Server:earth-one] at java.security.AccessController.doPrivileged(Native Method)
[Server:earth-one] at org.jboss.as.controller.remote.TransactionalProtocolOperationHandler$ExecuteRequestHandler$2.execute(TransactionalProtocolOperationHandler.java:153)
[Server:earth-one] at org.jboss.as.protocol.mgmt.AbstractMessageHandler$ManagementRequestContextImpl$1.doExecute(AbstractMessageHandler.java:363)
[Server:earth-one] at org.jboss.as.protocol.mgmt.AbstractMessageHandler$AsyncTaskRunner.run(AbstractMessageHandler.java:472)
[Server:earth-one] at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
[Server:earth-one] at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
[Server:earth-one] at java.lang.Thread.run(Thread.java:745)
[Server:earth-one] at org.jboss.threads.JBossThread.run(JBossThread.java:320)