Well, I spoke too soon. Just when I thought that all was well.

Just now, I took the bike out and the rear sensor worked immediately. The front sensor took a couple of miles before it registered the new pressure & temp.

It appears that this is an intermittent problem. I used to have the problem on the rear sensor. I swapped front and rear without reprogramming and the problem has moved to the front. So it must be the sensor.

I guess that I should try reprogramming it while it is on the front and see what happens. But I think that it is going to be a bad contact inside the sensor.

When I had it apart, I could see some surface mount components and the pressure sensor thing-a-ma-bob. I was hoping to see what ever they used to trigger the sensor when the wheel moves (a spring, a ball, something). I did not see anything. Next time I am in there, I will remove all the sealant and see if I can find the trigger mech.

Just following up ...