You have to look into the splits to see where the issue is though.
https://www.pro-football-reference.c...3/splits/2017/
The first attachment is "Downs" and "Yards to go" (not related to each other). 3rd down, he's only completing 59.42%, huge drop from 1st and 2nd downs, with 68.93% and 75.27%, respectively. I find it funny (or sad) on yards to go (7-9) that his Y/A is a paltry 5.4. No wonder why KC is average on 3rd downs at a 39.2% clip, 14th in the NFL.
The 2nd attachment is "Game Situations". Highlighted on those images is pretty telling for this attachment. Trailing with <2 min to go or <4 min to go, those numbers don't look good, with a Cmp% of 53.57% and 52.38% with a QB rating of 55.7 and 59.5. What's funny is.... no touchdowns.