Another update:
No vibration when driving from a cold start. I turned on the ?auto-hold? feature to see if this could be involved and this initially was working fine. After 5 minutes of driving, immediately after coming to a stop, auto-hold symbol went from white to green (normal function) and at that moment the same hum/vibration that I have described occurred. Then while continuing to drive, after multiple complete stops, the auto-hold would fail to engage (white light would not transition to green). Vibration sound continued after each transition from stop as described before. So now I?m wondering if it has something to do with the programming of the auto-hold. I tried turning the auto-hold on and off but it continued to fail to engage once I?ve driven for 5-10 minutes.
Has anyone else noticed this regarding the auto-hold after prolonged driving?