There is a good chance it's YOU who provokes her to be afraid of that spot. Very likely you expect it somewhere inside and it'll affect your seat and aids when you are in arena and especially getting close to that "bad" spot.
Can you ask someone to ride her just to see how she behaves? You can also just walk her around the arena from the ground till she calms down and then get on and work keeping her mind busy (transitions, change of direction, etc.).
"Life isn't about waiting for the storm to pass: it's about learning to dance in the rain..."
"When we are no longer able to change a situation - we are challenged to change ourselves."
"How people treat you is their karma; how you react is yours."