The last time I had this problem, I had used some PPG Concept paint that a customer had already bought. I sanded and buffed... but the orange peel and a couple sags came back!!!
I fielded the question about having the clear continue to shink over very long periods... and a guy who used only that system said to let it dry 2-3 months before i sand and buff!!! Screw that!
My own clear reaches a stable finish in 1-2 days, and never ever shrinks again! It might be the nature of your paint system, keeping it from being good for anything but force-drying... or requires a pefect mixture, ideal conditions, and flawless spray technique.
Personally... when a product proves to be too sensitive... I never use it again! }:-(