I will preface this by saying at least Jason's underscoring isn't that bad. His PCS is still 9th out of 30, and even a PCS as high as the highest one (the one Keegan got) would only leave Jason in 6th place instead of 7th. That said...
It seems a lot of times even when it's dead obvious to all that a skater new on the scene deserves great PCS, it takes a while for the judges to catch up. I wonder why that is. Do they need to go back to some secret judges' cabal and talk this over a few times before they can agree to give those points? Why does a skater have to be established in a particular competitive milieu before s/he earns respect? There will always be new kids on a scene, and they deserve to be scored fairly too. These athletes have finite competitive careers. You can't know that they have time to eventually get their rightful placement. This could be Jason's last junior Worlds. And a few points could be the difference between whether he ever gets a junior world medal.
And the ISU absolutely can fix this. They prodded and spanked judges until judges gave out transition marks that more closely reflected what's actually skated, and it really worked. If they tried, they absolutely could give memos and seminars and reminders until judges stopped deferring to the familiar.