Can you look at the switch in UPStart? Any parameters chaged there?
Is the "Remember Last Level" option selected or active?
Does it still dim up and down, go to on when the top rocker is tapped, snap full on when the top rocker is double tapped?
What happens when you double tap the bottom rocker?
Can you hear the micro switches inside click in both directions?
Can you place the switch in setup mode (5 fast clicks) using the bottom rocker?
A few more details would help.