Looks like leading edge pitch control horns. If the mast or transmission let go, the blade roots would rise up while the pitch links remain at the same point.
This would produce a brief period of low or even negative pitch. Kind of matches the footage at the 10 sec mark when the coning angle of the rotor disk goes negative.
I think the missing red blade flapped down enough to contact the fuselage and sheared off at the hub.