Here’s another thought.......

Is the cowl hood the “correct” distance from the windshield?

Attach a piece of string to the inside of the scoop, long enough to easily come out beyond the edge of the scoop.
At the top end of the track, see it the string is sticking out of the scoop.
It shouldn’t be, but if the scoop is too far away from the windshield, the inside of the scoop can be a low pressure area, instead of a high pressure area.
If the string is being sucked out of the scoop, the scoop opening is a low pressure area.