If I had to guess I would say the pressure plate was never right in the first place and likely a rebuilt unit? (sounds like TO contact with the clutch cover splines) I have leased a wagon that never had the clutch right (New, from Subaru) and they even replaced the entire car... and it was the same...Shudder on takeup, noisy and weak as heck on the old 2.5 non-turbo GT wagon.
I hope you can re-contact whomever did the clutch for you some 19k miles ago (unless you did it yourself..?)
There's only one thing worse than doing your own clutch (without the benefit of a lift) and that's doing it the second time, finding out (like I did on one of my old BMW's in high school) afterward that the pressure plate I had purchased (and installed myself) was faulty from the get-go.
I can sure feel your pain...