Thanks,737AvEng, for doing those tests. A while back I posted what if the #1 RA had failed to -7 ft before the approach was started but only went to retard on glide slope intercept. If you get another chance to try different failures would you try failing the RA to -7 ft before starting the approach? It might be something worth crosschecking before starting an approach or changing the software so the autoland will not arm if this fault happens again.
Corrosion around the antenna has been mentioned as a probable cause for this to happen so it probably will happen again.