Since you’ve got such a great picture, here’s some history on a few of the undertray bolts. See the two bolts left and right of the NACA ducts? They thread into rivnuts installed in a steel cross member. The bolts are very much larger than necessary, so there’s a tendency to over tighten them. This can result in the rivnut slipping in the cross member - since the bolt then just spins instead of coming out, the underbody tray is stuck.
Preventative measures are to coat the bolts in antiseize and only tighten them just snug (SWAG torque value: 15 lbs ft). No fear of these coming loose from vibration at that low torque value - my bolts haven’t fallen out since the new vehicle purchase of my 2011.
My factory bolts for that location are Torx drive button head. So either the factory ran out of a bolt spec (on your car or mine) or someone has swapped in different fasteners on your car.