I suggest you to contact Ivy team directly on this problem.
IMO, require the “dialog exit” to release memory is a bad idea. The users can close their tab/browser at anytime.
Short-term memory leak is a well known issue of JSF. If everything work as expected, the view’s memory will be released when the user session ended. But, in Ivy engine, something still be leaked by the Ivy process engine (perhaps the “dialog exit” was not called properly)