I noticed if you drag the slider very faster, it gives me some lag until 1 or 2 seconds to apply the changes.
Anyway good effects!
It happens to me as well, but I believe this lag comes from "Cursor is over slider". Because I noticed this only while dragging sliders and probably if you dragging it very fast cursor simply misses slider.
I could not find any good way to update sliders constantly. Some action like "Is slider dragging" would be really nice