The previous radalt faults were picked up, post accident. on the FDR. We do not,I believe, at this time know if they were ever recorded in the tech log or even if these previous occurrences were even noticed by the crews concerned. This crew may well have been, quite justifiably, unaware of these.
The crew were carrying out a cat 1 approach, during which the radalt is of little or no interest from a handling point of view.
So in effect, all the crew had to deal with was a misbehaving A/T and possibly, according to Boeing, the loss of one or both Flight Directors.