Dax would do the same thing. He would actually only play fetch inside but outside would chase after the ball, grab it and act like he was brining it back. He'd run past me or drop it a few feet away. About a month and a half ago, it's like switch flipped and now he'll play outside, actually shoving the ball into my hand most times.
Try walking away instead of waiting her out. Chances are, she'll grab the ball to follow you. When she does, praise her for it. Each time she brings the ball closer, praise. I still praise Dax and tell him to bring me the ball even when he's coming to me with it and praise heavily when he gives me the ball.