This was intentional. Popup lists for things like right-click menus would now allow for the same selection otherwise. For example right-clicking an item in Windward to bring up a popup list then choosing to link it in chat. First time would work, second time would not. Another example: right-clicking a player's name in chat and choosing to invite them to an instance. First time would work, second time would not. This was the reason for the change.
That makes sense. I think the issue here is that popup lists are being used in two very different ways:
1) Popup list as a context menu. This is what you have described. It does not exist while it is not being used by the user, so accessing its current value outside of the context of the onChange event does not make sense. The value doesn't really change, it is just temporarily selected.
2) Popup list as an option (such as screen resolution or video quality). This is how I am using it. It always exists, even if the user is not currently using it, so I want to be able to see what its current value is. The value does change, and it is important to know when if it has actually changed or if the user ended up choosing the same option. The value can also be set programmatically (not by the user).