How did this slip through?

Not being a patent attorney, I don't pay much attention to patent law. There are occasionally stupid patent decisions that get my ire up, but by and and large the ins and outs of patent procedure, but apparently two-thirds of the patent judges were unconstitutionally appointed. DoJ hasn't even denied it, and constitutional lawyers are all in agreement that it's not even close.

This could REALLY muck things up for the patent bar, which (unsurprisingly) didn't notice the error because patent attorneys are generally not accustomed to thinking about things constitutionally. Imagine all the patent hearings and appeals that must be redone, that are invalidated, all those millions once again at stake.