Context substitution variable in Aurena lobby page parameter - Apps10 UPD7 vs UPD9

We have some Aurena lobbies that use the context substitution variable #PERSON_ID# as the default value for the page parameter so that the lobby elements are by default based on the logged on user.  In Apps 10 UPD7 this works fine with no discernable performance issues.  After installing UPD9 we find that use of the context substitution variable causes elements to update slower or not at all (after a long delay), but typing in the person ID restores the performance to normal.  Has anyone else experienced this issue and/or does anyone know if the use of context substitution variables on Aurena pages has changed for UPD9?

Thanks!