The idea that somehow Pd or Ni can store astronomical amounts of H and release them suddenly to create these heat bursts by recombination is what one Russian researcher that confirms that the FPE exists unequivocally proposes,
Pd cannot suddenly release large amounts of hydrogen. That is why Pd-H and other hydrides are being developed to store hydrogen. If it could suddenly release the hydrogen, it would not be a safe method of storage. Hydrides do release more hydrogen when you heat them, but never all of the hydrogen, all at once.
In a closed cold fusion cell, if the cathode were to release a lot of hydrogen this would cause heating. The heating would happen in the headspace recombiner (catalyst). In an open cell, there is no free oxygen, so even if all of the hydrogen emerged in 10 minutes, it would not burn, and there would be no heat. It would just go out of the cell into the air. There is no oxygen and there is no recombiner, so there is no way it could ignite.
It is easy to estimate the total amount of hydrogen a palladium cathode can hold, and the heat this hydrogen can produce. It is far less than most cold fusion experiments produce. In Staker's experiment, it could not produce any heat at all, because there is no free oxygen, but if we pretend there is oxygen, we see that it can produce only 800 J. This is 142 times less than the experiment produced during the 28-hour heat burst, and 969 times less than the entire 48 day experiment produced. The heat was continuous, so there could not be any energy storage while it happened. Cold fusion continued after the burst, so the cathode could not have de-gassed. That would have stopped the cold fusion reaction.
Along the same lines, we know for sure that recombination did not cause that heat. It is far too small. So even if THH is right, and Staker is incapable of doing a grade-school level experiment in electrochemistry, recombination still cannot explain anything.