I was also one of the ones who went down in this turn. Similar story, was not going balls to the wall. Felt the back start to slip, then it caught traction and high sided. The guy who drove out also mentioned possible oil on the track. While we were waiting on the trailer, we walked out on track to look. You could see 2 faint dark stripes, almost like fluid was spraying out from the sides of a bike. Traced this back right to the spot I think I lost traction. Unfortunately no video. I was also unhurt, but cracked the frame of my bike, so it's getting rebuilt from the ground up.