Today my wife started to reverse the car off the drive, she stalled it (drive is quite steep) and the dreaded anti pollution fault lit up. She restarted the engine and the car wouldn't rev, I'm assuming limp home mode here. With no revs she stalled it again, when she restarted it for the second time the warning had extinguished and the revs were back to normal

Is this something I should be concerned about as perhaps an underlying problem, or just ignore it and hope for the best?
I do have my own theory on this but thought I would throw it open to the floor to see what everyone else thinks. Car is a 2004 C5 1.8 petrol VTR.
SteveT