could you create a jira issue for this ?
if you add a way for us to reproduce it (which property do we have to set to get your behaviour), then we probably can fix it quickly.
We did a few more tests and it seems that it's not a Jbpm bug. We are working with PostgreSQL 8 and we had not set a timezone parameter in the postgresql.conf file. We still have more tests to perform, but the problem apparently has been solved.
It's difficult to debug and test these timezone problems because it could work in one configuration and not in another, and since every system has it's own timezone configuration, it's difficult to know who is to blame.
Sorry for the false alarm.