Hi,
it is probably because jbpm 3.2.6 has enabled cache inside hibernate configuration by default. It is not yet provided in jbpm 4 I would say (at least as far as I know).
There is another thread already started about cache in jbpm 4.3, would be good to give it some ideas there and perhaps even to come up with an example how to enable it - I mean how to configure cache for entities.
Cheers,
Maciej