Had a similar fault myself
Between six and twelve months ago, I flew an 800 that displayed some similar issues.
On the first take off, the left rad alt continued to indicate -8 feet until passing about 2500'. This left the A/T stuck in TOGA and prevented the engagement of LNAV. Solution? Disconnect the A/T and fly the SID in raw data. Briefly confusing, but not a crisis.
On both arrivals back to the same airport, the left RA again read -8' (intermittently, rather than continuously), and the config horn sounded while down wind at 5-6000' decelerating from 250kts to clean speed. It also sounded the 50, 40, 30 calls of the flare while still at 5000'. At no point did the amber RA flag appear on the PFD, suggesting that the avionics did not recognise it as a false reading.
Did we bend the aeroplane? No - we just flew it normally. If you monitor what the aircraft is doing, such failures make virtually no difference to the flight. Before anyone asks, yes, the occurrences were reported in detail to the engineers, and no, I don't know what the causes of the intermittent error in the RA were. It was, however, restricted from Cat III ops until rectified.
My interpretation of the initial report is that a minor malfunction combined with the crew's failure to monitor the aircraft resulted in CFIT. The malfunction should certainly not have been enough to even mildly jeopardise the flight, had the crew been paying attention at a critical stage of flight. I will, however, remain open to new information regarding crew incapacitation or massive distractions from other problems.