So my horse has suddenly decided that she will not trot or canter the one long wall in the arena. She'll walk fine along it, she longes along it, but once we pick up a trot or canter, she shies and veers towards the center. If we turn and go the opposite direction, she'll walk, trot, canter fine along it with no issues. Any other spot in the arena, she will yield from the pressure, except that wall. Nothing has changed along that side, nothing new that could be spooky. Shadows weren't hitting along that side.
Does anyone have any insight on what may have happened and how to correct it? Thanks!