I think it's a combination of they miss Bieniemy, their OL is playing worse, the installed plays just aren't 'as good' (yeah Andy Reid calls the plays, but an offensive staff installs the gameplan and designs the plays and that seems to have taken a few steps back this year), the lack of a solid WR that Mahomes can depend on (was Juju last year) and Father Time catching up to Kielce finally. All of that together and you can see that Mahomes just isn't trusting everything in front of him. The entire offense just seems to be playing with a lack of focus and discipline that maybe Bieniemy brought because he is (according to rumors) kind of a hard ass.