A few facts:
1) Video evidence showed the co-pilot manually unlocking the feathering system early (Mach 1) and against normal procedures. (Mach 1.4)
2) The pilots did not manually deploy the feathers, but the feathers deployed anyway after being unlocked.
3) The rocket motor and propellant tanks were recovered with no signs of burn-through or breaching.
Source:
Virgin Galactic rocket plane deployed braking system prematurely | Spaceflight Now