org.jboss.dmr.client.ModelNode.fromBase64() fails

When sending the following request to the server:

{
    "operation" => "read-resource",
    "address" => [
        ("profile" => "default"),
        ("subsystem" => "osgi")
    ]
}

Parsing the response using ModelNode.fromBas64() gives the following exception on the client:
[ERROR] java.lang.RuntimeException: Illegal character 222
[ERROR] at org.jboss.dmr.client.DataInput.readUtfChar(DataInput.java:124)
[ERROR] at org.jboss.dmr.client.DataInput.readUTF(DataInput.java:101)
[ERROR] at org.jboss.dmr.client.ObjectModelValue.<init>(ObjectModelValue.java:53)
[ERROR] at org.jboss.dmr.client.ModelNode.readExternal(ModelNode.java:1293)
[ERROR] at org.jboss.dmr.client.ObjectModelValue.<init>(ObjectModelValue.java:55)
[ERROR] at org.jboss.dmr.client.ModelNode.readExternal(ModelNode.java:1293)
[ERROR] at org.jboss.dmr.client.ObjectModelValue.<init>(ObjectModelValue.java:55)
[ERROR] at org.jboss.dmr.client.ModelNode.readExternal(ModelNode.java:1293)
[ERROR] at org.jboss.dmr.client.ModelNode.fromBase64(ModelNode.java:1131)
[ERROR] at org.jboss.as.console.client.shared.subsys.osgi.OSGiPresenter$1.onSuccess(OSGiPresenter.java:109)
[ERROR] at org.jboss.as.console.client.shared.subsys.osgi.OSGiPresenter$1.onSuccess(OSGiPresenter.java:1)
[ERROR] at org.jboss.as.console.client.shared.dispatch.impl.DMRHandler$1.onResponseReceived(DMRHandler.java:96)
[ERROR] at com.google.gwt.http.client.Request.fireOnResponseReceived(Request.java:287)
[ERROR] at com.google.gwt.http.client.RequestBuilder$1.onReadyStateChange(RequestBuilder.java:395)
[ERROR] at sun.reflect.GeneratedMethodAccessor30.invoke(Unknown Source)
[ERROR] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
[ERROR] at java.lang.reflect.Method.invoke(Method.java:597)
[ERROR] at com.google.gwt.dev.shell.MethodAdaptor.invoke(MethodAdaptor.java:103)
[ERROR] at com.google.gwt.dev.shell.MethodDispatch.invoke(MethodDispatch.java:71)
[ERROR] at com.google.gwt.dev.shell.OophmSessionHandler.invoke(OophmSessionHandler.java:157)
[ERROR] at com.google.gwt.dev.shell.BrowserChannelServer.reactToMessagesWhileWaitingForReturn(BrowserChannelServer.java:326)
[ERROR] at com.google.gwt.dev.shell.BrowserChannelServer.invokeJavascript(BrowserChannelServer.java:207)
[ERROR] at com.google.gwt.dev.shell.ModuleSpaceOOPHM.doInvoke(ModuleSpaceOOPHM.java:129)
[ERROR] at com.google.gwt.dev.shell.ModuleSpace.invokeNative(ModuleSpace.java:561)
[ERROR] at com.google.gwt.dev.shell.ModuleSpace.invokeNativeObject(ModuleSpace.java:269)
[ERROR] at com.google.gwt.dev.shell.JavaScriptHost.invokeNativeObject(JavaScriptHost.java:91)
[ERROR] at com.google.gwt.core.client.impl.Impl.apply(Impl.java)
[ERROR] at com.google.gwt.core.client.impl.Impl.entry0(Impl.java:214)
[ERROR] at sun.reflect.GeneratedMethodAccessor28.invoke(Unknown Source)
[ERROR] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
[ERROR] at java.lang.reflect.Method.invoke(Method.java:597)
[ERROR] at com.google.gwt.dev.shell.MethodAdaptor.invoke(MethodAdaptor.java:103)
[ERROR] at com.google.gwt.dev.shell.MethodDispatch.invoke(MethodDispatch.java:71)
[ERROR] at com.google.gwt.dev.shell.OophmSessionHandler.invoke(OophmSessionHandler.java:157)
[ERROR] at com.google.gwt.dev.shell.BrowserChannelServer.reactToMessages(BrowserChannelServer.java:281)
[ERROR] at com.google.gwt.dev.shell.BrowserChannelServer.processConnection(BrowserChannelServer.java:531)
[ERROR] at com.google.gwt.dev.shell.BrowserChannelServer.run(BrowserChannelServer.java:352)
[ERROR] at java.lang.Thread.run(Thread.java:662)