Turf races are often run on the dirt or synthetic/all-weather track when the weather doesn't permit running on the turf. This often causes a large change in both the horses that are running in the race, and how the horses are expected to run.
EquinEdge updates all the numbers and picks when this happens. It may take up to 30 minutes for the system to re-crunch all the numbers. When it's done, you'll see OFF TURF where we show the surface of the race.