Now the big problem is that, in this single example of HAD documented by F&P, the input power has not ceased! So the cell was not "Death", and we can only talk of "Heat After Something", where the "Something" has not been highlighted and explained by the authors of the article.
I just skipped over the papers. As Mc Kubre already said a remaining voltage is to be expected! Decaying 4He from D-D fusion is strongly ordered due to magnetic momenta from excess flux. Thus the magnetic flux produces - expected by Maxwell source law - charge, what is equal to a certain voltage.
Additionally I checked (F&P) the ramp-up time of the heat and the timing of the heat after death. Both are absolutely conform with the current D-D fusion model we use. It's sad he left us that early!