I was riding her and there was a patch of light coming in from the arena that she was afraid of. She'd step around it or just stop right in front of it and refuse to walk through it quietly. So I got off her and lunged her and did some basic ground work that all required her to go through the light patch. After a while she gave in so I took her off the lunge and got back on.
I walked her through it and then trotted her through it, then cantered her through it. She still seemed a little unsure about it but she still went through it without doing her little dance first. Then I took her back through it at the trot, very calm and basic and she went to step around it again, got her front legs crossed or forgot to move a foot or something, and went down on her front knees and nose planted straight into the arena floor. I jumped off instead of sliding over her head and had my trainer/barn owner watch while I walked her to make sure she didn't have any noticeable leg injuries. She was fine but a bit shaken and after hosing her down I noticed she skinned her nose. It was red and looked like a really bad skid or rug burn. I washed her finished washing her face and let her back out to the pasture. We're going to take it easy tomorrow and work on that scary wall.
Poor baby. She was shaking when I walked her out of the arena. Neither of us were expecting a nose plant but luckily neither of us were really hurt either. Something in that arena down that wall has been making a lot of horses nervous apparently, not just her. At least time I'm 99% sure it was the light patch (since I normally do arena riding at night so it's not there). But any time of day a bunch of the horses don't like 20 feet of that wall and nobody knows why! Weird.