Against a team like Idaho State, who literally NEVER plays a tight end and instead plays four wide receivers, the Griz have to get home in the box and knock the QB off the spot or its going to be a mismatch with open receivers all day long.
Montana plays six men in the box. They bring between 4-6 on every single play, especially when Idaho State was throwing. That means if the Griz bring five, Idaho State is playing 7-on-6. If the Griz bring six, Idaho State is playing 7-on-5.
You can mitigate it by hitting Cooke or covering in the slot.
No coincidence that Montana's defense buckled down when Peyton Wing, their best cover linebacker, got back in the game and the defense started playing Micah Harper man-to-man against one of the slots. That forced Cooke to need an extra half-second and the rush was able to knock him off the spot. Once he wasn't in a complete rhythm, the Griz were able to take the upper hand.