> which doesn't seem to be the case here.
That's the thing about subtle errors. They never seem to be the case, even when they are the case. Remember the superluminal neutrino claim a few years back? There are endless ways an experiment can go awry and present misleading results.
Here, there's going to be a very large background (of neutrons and photons) from the process they are using. I wonder if they didn't handle background subtraction quite right.
You're implying that a a subtle error would be sufficient to explain the observations, which doesn't seem to be the case here.
Gross experimental or interpretation errors are a possibility, of course, but are correspondingly less likely.