I have a slight vibration that is felt through the entire car when braking downhill at highway speeds. The vibration doesn't affect the steering wheel and doesn't necessarily feel like it's coming through the braking pedal but rather feels like the whole car is 'slightly' vibrating with a rumbling(ish) sound.
I took my car to the dealership and they said nothing was wrong although I have reason to believe they didn't actually do much investigation. They said they took it for a test drive around the local area but after reviewing the dashcam footage (that I'm guessing they didn't notice I have installed) they simply went down the road, braked slightly fast, and the turned around and went back to the dealership.