A new property added after backup() was applied is not removed when restore() is called

[gorokhovvs]

Hi there,
I've got an issue. I'm migrating my code from CanJS v2 and using define maps instead of can.Map.
As I see can-map-backup uses this.attr(props, true); when restoring initial value. And it removes all the protperties added during backup. But can-define-backup just assign stored properties this[prop] = props[prop]; - and it doesn't remove new props.
Is this an expected behavior or this will be fixed in near future?

BTW Will it work as a temporary solution if I will use this.update()?