It appears as thought she's built downhill, so she's going to be heavy on the forehand. Her canter looked like a typical, downhill canter. Nothing strange. It looks like she needs to learn how to collect and bring her butt under her and use it; she's simply running on her forehead at the moment.
I've never seen a horse bend on its own while lungng in the roundpen unless it had extensive dressage training, but perhaps she just needs a tune-up lesson on how to bend under saddle (assuming it's nothing the vet or chiro can fix.)
Good luck, have fun! ;D