In those cases the TR deployment is symmetrical, starts at idle, and power goes up to some predetermined limit that's flight tested and certified to not pose any issues wrt. efflux blanking out controls, etc. Not sudden, on one side, and at cruise or higher power.
Understood, but as the aircraft had procedures to deploy reverse thrusters inflight, it seems reasonable that procedures were in place if only one of the pair deployed? This may be a good learning experience on that adventure? (ie on the Concorde, when using rev thrust to slow from supersonic, and only one deployed, what was SOP, that seems a bit of an extreme case)