we are facing a strange JPQL issue in WAS and

The JPQL is as below.
select obj from Customer obj left outer join fetch obj.addresses where obj.customerId =:clientId

And the given customer has 2 addresses, and in Customer class address List is lazy attribute. 

And in DAO class, if we get the query.getSingeResult(), its failing as 'Non unique result exception'.

It supposed to return one customer object, with 2 address inside list, instead it returns 2 customer objects, and both are having 2 address objects.

while JPQL converts into native SQL during run-time, oracle returns 2 records, and hiberante's responsible to pack the data in to customer object and return one object. But its not happening.

But in websphere, this works fine, also works in Tomcat,Weblogic and OC4J servers.

Hence i believe there is some issue in WAS and 
If any one knows to solve the problem, pls let us know.