I hear a single click when I brake

This problem has been coming and going since about 1k miles. I now have 30k and it happens 99% of the time now. When I press the brake pedal, I hear a single click. It can be heard over the radio although I don't listen to the radio all that loud. The sound is annoying and even now, it might disappear for a few days but it has always come back.

Sometimes it happens when I brake very slightly other times the pedal needs to be pushed hard(on a hard brake). If I tap the brakes(down and all the way back up, down again) it will make it happen twice. The noise is there even when the car is stopped and in park. Problem is, it goes away, sometimes for 20 or 30 miles, other times a few hundred.

Dealer heard the noise, said they never heard it before and looked around but didn't see anything to fix.

My car is a 2016 model 4. Any ideas?

 

Yes, it makes the noise when the car is off. The noise sounds like it is coming from the pedal area and not related to the brake lights. My advisor went into a new Prius and he was able to hear the noise in those. I do have Toyota calling me today to discuss the issue. My advisor agreed with me and said that the noise is very annoying. I can't imagine driving the car with it for the rest of the cars life.