There is a bug in validation code, in org.jboss.resource.connectionmanager.InternalManagedConnectionPool class validateConnections method. It is easily reproducible by the following example. You have a set of 3 connections in the pool, and when you run this validation code, the fist one is not valid and the following 2 are valid. As you do not update "destroyed" variable to "false" on every iteraion, those 2 valid connections do not return to the pool, resulting in two ESTABLISHED connections going out of pool control. Also, resource adapter counters don't get updated, resulting in an inconsistent status.

In JBoss forum reference I have provided affected code and a solution developed by me as a suggestion