Has she always done that with her arm or is it just since she's taken up archery? I can hyperextend my arm into that position, but I feel it in my shoulder and neck muscles so I was wondering if she's pushing the bow causing (or exagerating) the hyper extension, or if that's just how her arm sits.
Ideally the bones in her front arm (in her case her left) should be aligned so that the force is going through the bones, rather than being held in place by the soft tissue. It is possible to learn how not to hyperextend, but it does take a lot of effort before it becomes subconsious - it might be worth consulting a physiotherapist for some range of motion training to reduce the risks of injury in the future.
It's hard to see from that photo but it's possible that her front shoulder is also a bit high and with the hyperextension it's quite probable that her shoulder is taking more strain than it should - my suggestion is to familiarise yourself with what the shoulder position should look like and get her to draw her bow so you can see what is going on. This is best done with her wearing something that covers as little of her shoulders/shoulder blades as possible (which is why I haven't suggested you post the pictures on here) or with a couple of mirrors she can see for herself.
Most of the information online will have pictures of men, usually with well defined muscles so it might not be as obvious with your daughter - for a comparison have a look at some of Erika Anear's youtube videos - a lot of them are
compound but the shoulder should look the same