For example why does Notre Dame cover easily today vs Navy and why didn't TCU cover last night giving up a meaningless TD at the end?
The answer:
Alumni/Boosters.
Coaches feel the pressure to give up money they receive from alumni/boosters they receive in off season. So once a season the coaches circle a game they think they can run up the score or keep it under the spread and notify alumni/boosters before the game. This is their little thank you gift for all their support. Alumni/boosters proceed to hammer this game and get rich.