I think Mahomes is actually 11-7. Last year the New England game got bumped to primetime due to COVID.

This is because we sold the naming rights to the field

Curse of the GEHA

10-8

2018

@ Denver W
@ NE L
Cinci W
@ LAR L
LAC L
@ SEA L

2-4

2019

IND L
@ DEN W
@ LAC W
@ CHI W

3-1

2020

HOU W
@ BAL W
NE W
@ BUF W
@ LV W
DEN W

6-0

2021

@ BAL L
BUF L

0-2

Total:
11-7

What win am I adding and what loss am I missing?

I forgot the @BUF win

2019 we lost against GB at home, of course that was without Mahomes.

COVID scheduling created some weird tweener games, for sure. I would think they would count simply because they were on Monday night but I'm unsure if they'd be excluded for whatever reason.

That's the stat comparison I was looking for.
Seems a little drastic, huh?

Prime time games tend to be divisional foes or marquee matchups, so that increases the difficulty level.

But really, four of those seven losses came in Mahomes' first year as a starter (and included road losses to the SB-bound Pats, the SB-bound Rams, and Russell Wilson). Since then he's 9-3. I don't think there's really much there there.