I'm having an annoying problem with my rear Deore shifter. The thumb paddle (to move from a smaller to a larger cog) will not spring back on its own after being pressed. If you give it a slight nudge it will spring back into place. If you use the finger trigger (to move to a smaller cog) it also makes the thumb spring back into place.
LBS said to lube it, and I did thoroughly, with the lube they recommended.
I'm about to throw out this thing, it's been finicky for a couple months. Never crashed...