When changing viewport focus fast between two cards, the focus viewport glitches visually slightly

[db0]

This seems to happen because I don't instantly clear out the old object, to give time to tween the viewport to alpha, if there's nothing else in focus. Because of this, when I switch two cards fast, there's a millisecond where both duplicate card objects exist under the camera, and you see the old one as the camera focuses on the new one.