Rout et al don't seem to think it is ionizing radiation. The first paragraph of their Conclusion section ends with
"The energy of the emissions from palladium hydride appears to be small, as it is able to affect radiographic films (>2 eV) and thermoluminescent dosimeters (>3 eV) but did not ionize (>10 eV, average 30 eV/ion pair) gases."
From their description, I think that the Gordon lab should expect to pick up their posited ionizing radiation with a Geiger counter run over the working electrode when it is outside their assembly.
They did in under very mild conditions, and it's directly related to temperature as shown by Gordon and Whitehouse, but nevertheless, the important and grossly overlooked fact is that there is an emission of some kind of radiation, this is the important fact, and if you care to see the presentation and watch the zoom discussion session, you will see why is relevant.