Error RPC después de la actualización GWT 2.3

Question

Después de actualizar a GWT 2.3, algunos de mis servicios de RPC ya no funcionan y fallan con "la respuesta no pudo ser deserializada". Parece que les sucede a los servicios que devuelven objetos que usan objetos de fecha que se anotan con @temporal (temporaltype.timestamp). Utilizo Gilead 1.3.2 y Hibernate 3.6 y no tuve problemas con GWT 2.2. ¿Alguna idea de lo que podría estar pasando o cómo comenzar a depurar?

Aquí está el rastro de la pila:

com.google.gwt.user.client.rpc.IncompatibleRemoteServiceException: The response could not be deserialized
  at com.google.gwt.user.client.rpc.impl.RequestCallbackAdapter.onResponseReceived(RequestCallbackAdapter.java:221)
  at com.google.gwt.http.client.Request.fireOnResponseReceived(Request.java: 287)
  at com.google.gwt.http.client.RequestBuilder$1.onReadyStateChange(RequestBuilder.java:395)
  at sun.reflect.GeneratedMethodAccessor33.invoke(Unknown Source)
  at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImp l.java:25)
  at java.lang.reflect.Method.invoke(Method.java:597) 
  at com.google.gwt.dev.shell.MethodAdaptor.invoke(MethodAdaptor.java:103)
  at com.google.gwt.dev.shell.MethodDispatch.invoke(MethodDispatch.java:71)
  at com.google.gwt.dev.shell.OophmSessionHandler.invoke(OophmSessionHandler.java:167)
  at com.google.gwt.dev.shell.BrowserChannelServer.reactToMessagesWhileWaitingForReturn(BrowserChannelServer.java:326)
  at com.google.gwt.dev.shell.BrowserChannelServer.invokeJavascript(BrowserChannelServer.java:207)
  at com.google.gwt.dev.shell.ModuleSpaceOOPHM.doInvoke(ModuleSpaceOOPHM.java:132)
  at com.google.gwt.dev.shell.ModuleSpace.invokeNative(ModuleSpace.java:561)
  at com.google.gwt.dev.shell.ModuleSpace.invokeNativeObject(ModuleSpace.java:269)
  at com.google.gwt.dev.shell.JavaScriptHost.invokeNativeObject(JavaScriptHost.java:91)
  at com.google.gwt.core.client.impl.Impl.apply(Impl.java)
  at com.google.gwt.core.client.impl.Impl.apply(Impl.java)
  at com.google.gwt.core.client.impl.Impl.entry0(Impl.java:214)
  at sun.reflect.GeneratedMethodAccessor27.invoke(Unknown Source)
  at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
  at java.lang.reflect.Method.invoke(Method.java:597)
  at com.google.gwt.dev.shell.MethodAdaptor.invoke(MethodAdaptor.java:103)
  at com.google.gwt.dev.shell.MethodDispatch.invoke(MethodDispatch.java:71)
  at com.google.gwt.dev.shell.OophmSessionHandler.invoke(OophmSessionHandler.java:167)
  at com.google.gwt.dev.shell.BrowserChannelServer.reactToMessages(BrowserChannelServer.java:281)
  at com.google.gwt.dev.shell.BrowserChannelServer.processConnection(BrowserChannelServer.java:531)
  at com.google.gwt.dev.shell.BrowserChannelServer.run(BrowserChannelServer.java:352)
  at java.lang.Thread.run(Thread.java:680)
Caused by: com.google.gwt.user.client.rpc.SerializationException: java.sql.Timestamp/1769758459
Caused by: com.google.gwt.user.client.rpc.SerializationException: java.sql.Timestamp/1769758459
  at com.google.gwt.user.client.rpc.impl.SerializerBase.getTypeHandler(SerializerBase.java:153)
  at com.google.gwt.user.client.rpc.impl.SerializerBase.instantiate(SerializerBase.java:114)
  at com.google.gwt.user.client.rpc.impl.ClientSerializationStreamReader.deserialize(ClientSerializationStreamReader.java:111)
  at com.google.gwt.user.client.rpc.impl.AbstractSerializationStreamReader.readObject(AbstractSerializationStreamReader.java:119)
  at com.lensoo.shared.entity.Course_FieldSerializer.deserialize(Course_FieldSerializer.java:320)
  at com.lensoo.shared.entity.Course_FieldSerializer.deserial(Course_FieldSerializer.java:405)
  at com.google.gwt.user.client.rpc.impl.SerializerBase.deserialize(SerializerBase.java:95)
  at com.google.gwt.user.client.rpc.impl.ClientSerializationStreamReader.deserialize(ClientSerializationStreamReader.java:113)
  at com.google.gwt.user.client.rpc.impl.AbstractSerializationStreamReader.readObject(AbstractSerializationStreamReader.java:119)
  at com.google.gwt.user.client.rpc.impl.RequestCallbackAdapter$ResponseReader$8.read(RequestCallbackAdapter.java:106) 
  at com.google.gwt.user.client.rpc.impl.RequestCallbackAdapter.onResponseReceived(RequestCallbackAdapter.java:214)
  ... 26 more 
  ... 26 more