Update: After the dealer inspected and tested the brake pedal it was determined it was normal. It was simply the solenoid sensor that does the e-pedal braking. The sound is generally only audible when the audio system is off, windows closed, and A/C on low. Must not have heard it previously as I usually had music playing at medium level. It was definitely not the lug nuts as they rotated my tires on this same visit.
I actually test drove a PLUS unit on that same visit, and heard the same sound.
jdcbomb wrote:Starting after my 2nd month of ownership in near freezing weather, my 2018 Sep (bought in Dec) vehicle made a single "click" sound every time I depress the brake pedal (click happens on the initial push, nowhere else during its travel). Warmer weather did not stop the click. It doesn't seem to affect the operation of the pedal, but the sound gets annoying especially how quiet it is inside. I'll get it examine during a visit to the dealer in a couple months. No other issues observed.