2011 chevy, 35,000 miles.
Several DEF issues:
-replaced sprayer nozzle
-multiple reprograms attempting to make my def last longer than 1200 miles. Dealer claims one must fill the whole tank up completely, or it doesn't reset itself correctly, whatever that means.
It seems to be fixed now, though I only get 4500 miles on my def tank. Decided not to worry about it anymore.
One problem I have found, when filling up the DEF tank, is that its hard to get the last gallon or so of DEF into the tank, as it has trouble getting the air out of the tank, as the fluid is being poured in.