I'm no physicist, so I am just guessing. It could be some phenomenon similar to what we see in emission spectrums, where a pure source can emit photons at mul

I'm no physicist, so I am just guessing. It could be some phenomenon similar to what we see in emission spectrums, where a pure source can emit photons at multiple precise energy levels. except that in the case of particles with mass(apparently neutrinos have a mass) this would result in a difference in speed. Not a big enough difference to be noticed on 700 km , but enough to make a 4 yr difference on 170kly. Of course this is still wild speculation without much background.