Brake grinding/screeching

I have the problem that I have seen others talk about. Sounds like a small rock is caught in the brakes and thus causing a grinding and screeching noise. Drove it for about 12 miles and then decided to go back home and switch cars.

I am unable to see anything or get my fingers in there. Others I've seen talk about this said it cleared itself after driving it a bit--as if a rock that was lodged became un-lodged. Our driveway is pebble and as we set off I heard a clinking, as if something (a small rock) was bouncing around in/on some metal. Took a turn and then it became the grinding/screeching.

I guess the timing is convenient in that I already have the car scheduled to go in on Monday for a "Driver Restraint System Fault" warning/error that came up yesterday. My concern is that I've seen several others talk about this problem so it seems the car is prone to it.

Following a heavy rain the night before, I noticed a grinding noise as I pulled out of the garage the next morning. It went away after a few miles and hasn't returned. I'm not alarmed but am monitoring.

From the i3 Facebook group, I got some advice to bend back the weird rotor cover shield. Did that, rock dropped out, and now no problem.