I just commited minor changes to ExecutionImpl that fix the copy when destroying a scope : if the fields are directly accessed, the copied value is null.
You have to use the getters and setters to make the value pass through hibernate proxy.
my bad. sometimes, you can be sure that an object is initialized when you see that before a getter or setter has been accessed. in those case sometimes i dare to use direct field access instead of getters/setters.