When we removed the top cowling on my CC to attach the prop balance instruments I discovered fretting between the top and bottom cowling at the two screw just outboard to the left and right of the spinner.
It is fairly severe. That seems to be a weak point in the cowling design because of the air inlet holes and the prop shaft hole.
I tightened the screws with more torque than I would consider normal when the cowling was reinstalled.
I'll see what hapens now.
You might want to check your cowling screws in that location.
Bill