Dan thinks the parking brake was on, and that the anti-skid did operate with parking brake applied, blames it on 91/135 "knuckleheads".
Doesn't explain if he confirmed that the anti-skid actually works with PB applied, also no way to know yet if the pilots set the brake or if it malfunctioned. Brakes do malfunction, ask me how I know.
https://www.youtube.com/watch?v=f7J6p7i9yNA