I would strongly suggest to park in reverse a couple of times and check for any break squealing. Preferably as soon as you get in the car before it gets hot.
Mine got detached from the corners, some people have claimed the bolts fell off. Mine broke. Warranty replace, still on back order. Not planning to put it back on......
I had the same issue until I realized the Dealer deliver my 4runner with 53 psi of air in each tire. Substantially better now with tires at 33psi as per my door sticker.
Dealer replicated the issue and opened a TAS for that. Basically they are requesting approval for a warranty fix. I doubt it will be addressed soon since there is no TSB for it yet. I will update with updates as I get them.
Took it to the dealership on June 12 to address the hood flutter issue (on top of the air dam falling off, windows electrical issue, and the squealing noise on brakes).
Dealership acknowledge the issue without a solution - the more people addresses this issue the sooner a TSB will be populated...