Has entity instance pooling been disabled in the latest releases?
In 2.4.3 and 2.4.1, accessing a bean that has been passivated causes the constructor to be called (i.e. a new instance is created). This did not happen in 2.4.0. This implies that when a bean is passivated, the instance is destroyed rather than returned to the instance pool.
I've seen some posts in a similar vein relating to SLSBs and MDBs but nothing with respect to entity beans.