Noticed that nowhere is the StatefulBeanContext txSynchronized property ever set to "true". Only call to the setter is in SessionSynchronizationInterceptor.SFSBSessionSynchronization.afterCompletion(), which sets it "false".
Don't know enough about the use of this field to know the effect of this, but it seems like either a bug or a no-longer needed property.
i'll have to trace why I had that in there...