`Circumscribe` combined with `lag_ratio` causes the box to be drawn after the animation finishes

[sudgy]

Consider the following scene:

class Test(Scene):
    def construct(self):
        m1 = Dot(LEFT)
        m2 = Dot(RIGHT)
        self.play(AnimationGroup(Circumscribe(m1), Circumscribe(m2), lag_ratio = 0.5))
        self.wait()

When rendered, the box on the left starts the animation, then the box on the right starts the animation, but then after the first one finishes and before the second one finishes, the box for the first one just sits there instead of disappearing.