So the only differences I see between your test and mine are:

1. You use a Stateful SB, whereas I use a simple local bean
2. You use CMT, whereas I used BMT
3. You use Hibernate native bootstrapping, I use JPA bootstrapping

Other than that everything is the same. So the problem would seem to lay somewhere in those differences. I am playing around with your test some to narrow down what specifically causes the problem.