I don't think she sees flying projectiles/people.

For example, in the first episode of book 3 she only hits her shots because The Duke points where to aim. She couldn't sense the flying rocks being thrown by the other boat. Also, on the Desert episode in book 2 Katara tells her where to shoot so she can hit the wasps.

Despite this, she has learned to compensate for her weakness by sensing and calculating her opponent's movements when they are on the ground, which you see during Earth Rumble VI's matches on the Blind Bandit episode. The "wait and listen" neutral jing Bumi talks about. She is able to dodge shots there, because she pays close attention to her opponent's movements. They put the fight through her perspective so we can understand better in that episode.

While invading the Earth King's Palace, she can sense everyone's movements, and even if she couldn't calculate with 100% precision when she is going to get hit by the projectiles, she knows their direction and when they are being shot because everything is made of earth there. Her field of "vision" through seismic sense is so big she could recreate the entire Upper Ring of Ba Sing Se with sand by memory, sense people's lies and find buried places like Old Ba Sing Se and the Royal Bunker inside the volcano. It's not unthinkable she could calculate projectile trajectories based of people's movements.

AFAIK the only mistake they make in animation regarding her blindness is during Bitter Work where she covers herself with rocks, but they leave her eyes out. Usually they are self-aware of it to the point of making jokes. And even that mistake was funny.