The company is doing electrical testing for bad traces, bad resistance in the joystick and is also setting aside any nubs that feel loose or gritty.
I'm pretty sure that test is way better than any of our "move them around for a while to see if they work fine"-testings.
While we don't know yet if this is related to the few nubs that kept sticking in one direction (those nubs are still on the way to the manufacturer to be tested), it could well be the reason. If the rubber is a bit too gritty or thick, the resistance is wrong and it could lead to a sticking nub.
500 tested nubs (tested in one day! ) are ready to be shipped today to the board manufacturer. Shipping takes one day, so if we're lucky, by next week more boards will be ready.