occasional shiny when pressing new wave in web client

When I press New Wave in the web client I occasionally get the following shiny. I get this shiny both on my own test instance and on waveinabox.net. I wonder if this is a very recent regression. The following stack trace is from waveinabox.net.

Stack trace:

Token: 1306093453274
One or more exceptions caught, see full set in UmbrellaException#getCauses
Unknown.$fillInStackTrace (StackTraceCreator.java:147)
Unknown.fillInStackTrace (StackTraceCreator.java:387)
Unknown.RuntimeException_2 (Throwable.java:46)
Unknown.UmbrellaException_0 (com.google.gwt.dev.jjs.ast.JProgram:0)
Unknown.$doFire (SimpleEventBus.java:214)
Unknown.$fireEvent_0 (SimpleEventBus.java:103)
Unknown.$fireEvent (HandlerManager.java:101)
Unknown.$fireEvent_1 (Widget.java:103)
Unknown.fireNativeEvent (DomEvent.java:116)
Unknown.$onBrowserEvent (Widget.java:151)
Unknown.onBrowserEvent (Widget.java:137)
Unknown.onBrowserEvent_0 (Composite.java:55)
Unknown.dispatchEvent_1 (DOM.java:1264)
Unknown.anonymous (DOMImplStandard.java:187)
Unknown.entry0 (Impl.java:214)
Unknown.anonymous (Impl.java:57)
Caused by: Token: 1306093453277
One or more exceptions caught, see full set in UmbrellaException#getCauses
Unknown.$fillInStackTrace (StackTraceCreator.java:147)
Unknown.fillInStackTrace (StackTraceCreator.java:387)
Unknown.RuntimeException_2 (Throwable.java:46)
Unknown.UmbrellaException_0 (com.google.gwt.dev.jjs.ast.JProgram:0)
Unknown.$doFire (SimpleEventBus.java:214)
Unknown.$fireEvent_0 (SimpleEventBus.java:103)
Unknown.$fireEvent (HandlerManager.java:101)
Unknown.onClicked (SearchPresenter.java:151)
Unknown.onClick_16 (ToolbarClickButton.java:57)
Unknown.$handleButtonClicked (HorizontalToolbarButtonWidget.java:109)
Unknown.onClick_15 (HorizontalToolbarButtonWidget_BinderImpl.java:44)
Unknown.dispatch_1 (ClickEvent.java:53)
Unknown.$doFire (SimpleEventBus.java:204)
Unknown.$fireEvent_0 (SimpleEventBus.java:103)
Unknown.$fireEvent (HandlerManager.java:101)
Unknown.$fireEvent_1 (Widget.java:103)
Unknown.fireNativeEvent (DomEvent.java:116)
Unknown.$onBrowserEvent (Widget.java:151)
Unknown.onBrowserEvent (Widget.java:137)
Unknown.onBrowserEvent_0 (Composite.java:55)
Unknown.dispatchEvent_1 (DOM.java:1264)
Unknown.anonymous (DOMImplStandard.java:187)
Unknown.entry0 (Impl.java:214)
Unknown.anonymous (Impl.java:57)
Caused by: Token: 1306093453278
(TypeError): Cannot read property 'waveId' of null
stack: TypeError: Cannot read property 'waveId' of null
at $openWave (http://waveinabox.net/webclient/E5D8C2F096E147B88924843A159FC483.cache.html:22532:193)
at $onCreateRequest (http://waveinabox.net/webclient/E5D8C2F096E147B88924843A159FC483.cache.html:22595:3)
at Object.dispatch_17 [as dispatch] (http://waveinabox.net/webclient/E5D8C2F096E147B88924843A159FC483.cache.html:23162:64)
at $doFire (http://waveinabox.net/webclient/E5D8C2F096E147B88924843A159FC483.cache.html:4318:78)
at $fireEvent_0 (http://waveinabox.net/webclient/E5D8C2F096E147B88924843A159FC483.cache.html:4389:3)
at $fireEvent (http://waveinabox.net/webclient/E5D8C2F096E147B88924843A159FC483.cache.html:4224:5)
at Object.onClicked (http://waveinabox.net/webclient/E5D8C2F096E147B88924843A159FC483.cache.html:24087:59)
at Object.onClick_16 [as onClick_1] (http://waveinabox.net/webclient/E5D8C2F096E147B88924843A159FC483.cache.html:35611:217)
at $handleButtonClicked (http://waveinabox.net/webclient/E5D8C2F096E147B88924843A159FC483.cache.html:35004:253)
at Object.onClick_15 [as onClick] (http://waveinabox.net/webclient/E5D8C2F096E147B88924843A159FC483.cache.html:35174:3)
arguments: waveId,
type: non_object_property_load
Unknown.$fillInStackTrace (StackTraceCreator.java:147)
Unknown.fillInStackTrace (StackTraceCreator.java:387)
Unknown.JavaScriptException_0 (Throwable.java:46)
Unknown.caught_0 (Exceptions.java:29)
Unknown.$openWave (WebClient.java:286)
Unknown.$onCreateRequest (WebClient.java:141)
Unknown.dispatch_17 (WaveCreationEvent.java:30)
Unknown.$doFire (SimpleEventBus.java:205)
Unknown.$fireEvent_0 (SimpleEventBus.java:103)
Unknown.$fireEvent (HandlerManager.java:101)
Unknown.onClicked (SearchPresenter.java:151)
Unknown.onClick_16 (ToolbarClickButton.java:57)
Unknown.$handleButtonClicked (HorizontalToolbarButtonWidget.java:109)
Unknown.onClick_15 (HorizontalToolbarButtonWidget_BinderImpl.java:44)
Unknown.dispatch_1 (ClickEvent.java:53)
Unknown.$doFire (SimpleEventBus.java:204)
Unknown.$fireEvent_0 (SimpleEventBus.java:103)
Unknown.$fireEvent (HandlerManager.java:101)
Unknown.$fireEvent_1 (Widget.java:103)
Unknown.fireNativeEvent (DomEvent.java:116)
Unknown.$onBrowserEvent (Widget.java:151)
Unknown.onBrowserEvent (Widget.java:137)
Unknown.onBrowserEvent_0 (Composite.java:55)
Unknown.dispatchEvent_1 (DOM.java:1264)
Unknown.anonymous (DOMImplStandard.java:187)
Unknown.entry0 (Impl.java:214)
Unknown.anonymous (Impl.java:57)