That's called a partial A symmetric collapse. It means the flyer is light on the glider not over 100 percent loading and he hit some nasty air that was more of a tick not an actual collapse. Today's modern wing very seldom do that unless in bad air or pilot is at low load rate and bad air. I will have your customers engine her on Thursday as I wanted to get it her before holidays. Any questions all ways feel free to ask and try to fly mornings and late evenings unless at beaches were you can fly all day and always check weather.