I have a couple friends who it has happened to, one more than once (!!) so I was very prepared for that as an option. Especially since this round they had like 181 applicants where I think the last time I applied it was more like 100, it makes sense that the "15-20%" is perhaps not a very good estimate of how many folks get funded, and perhaps its more shaped by budgets.
the program officer referenced some of the feedback in the "good" review I recieved as justification, as well as expanded a bit on their own concerns, and said that the panel reccomended more people for funding than they could fund (this seems to be usual).
re: notification - fastlane status changed, reviews are available, and my PI was emailed - the student/co-PI's dont get emails.