Your's is the 9th mustang to report this in a forum by my count.
Mine is the 10th then.
Last week Wednesday. Clear Texas morning. No water or oil on the road. Merged into a road turning crisply 90 degrees to the right and then go up a hill. After shifting to 3rd gear around 40mph the car lost power and the traction control light was blinking. It felt like I had a flat tire on the front left side. I stepped on the brakes and a grinding noise came from the front! I released the brakes and the grinding stopped. I applied the brakes again and the grinding was louder that time. Since I had space and the car was stopping by itself anyway, I released the brakes to let the car stop by itself. Once I was on the side of the road I turned off the engine and got out to inspect the tires for a flat and see if the there was anything stuck underneath that I had not noticed. Nothing looked out of order. Got back in, started the car and pushed the traction control button to turn it off and drove. A few seconds after I shifted to 3rd the car started to swerve all over the road. It felt like each side was braking in turn. I briefly applied the brakes only to hear the grinding noise again so I let it stop by itself. Once the car stopped I turned off the engine and was on the phone for a few minutes. Since the phone's battery was low I decided to go back home to call the wrecker from there so I started the car, turned off the traction control again and headed home. The car drove ok for that mile so I decided to venture the drive to the Ford dealer. There they told me they were busy and short-handed to they would not be able to check the car for a few days.
Since Wednesday morning the car has not had the problem, although I have been driving very gingerly because I don't trust it.