HN39:
Since the FD pushbuttons were not selected OFF, each time valid ADR data was recovered, the FD's would have reappeared, and the FD vertical mode at recovery would have defaulted to V/S and the FD vertical command cue would have commanded the vertical speed existing at that time. This V/S would also be displayed in the FCU window, just as if selected.
Deselection of the FD avoids this.