I experienced a single instance of a "Service DEF - See Dealer"
that turned out to be thrown by codes P204F / P20E9 on my 2014 EcoDiesel. I cleared the codes, drove 30 minutes to clear the emissions condition, and the problem has never recurred.
However, approximately six months later a flash fix has been released as an RRT:
RRT 14-107/TSB 18-023-15
Just wanted to record this for anyone else who experiences these codes.