I first wrote a form fill to the dealership service department where I'd purchased my unit, then spoke with a SA.Toyota bought back my '19 for this issue and my '20 has the same problem.
So to sum up all I've read:
the fix is quite effective and I should ask for a loaner/rental when making the appointment.
Anything I'm missing? Any evidence I should capture in photo/video before taking it in? My biggest concern is a local dealer doing the work - the risk of error and damage to my vehicle is much higher outside of the factory (though those fears will not prevent me from taking it in and finally getting the DTE I was expecting a couple of years ago.
I simply told him the unit (mfg'd 7/19) had the issue, that I was interested in getting the "fix", and what, if any, parameters he wanted me to fulfill prior to presenting the unit at his desk.
He asked that I bring it in at the appointment date/time with as little gasoline in the tank as comfortable.
Done and done.