Yesterday's log entry reported that many (most?) UDP datagrams are not getting through to the car. I then guessed that since the display was closer on the PCB than on the stripboard prototype, it might be interfering with the WiFi signal.
I tested that theory last night. First I put another socket plugged into the first to increase the distance between the WiFi antenna and the display. NO effect was noted.
Next I had a great idea - after the display showed the current IP address, I removed it completely and depended on the actions of the car to show me when datagrams were being received. NO effect was noted.
I'm quite sure that an unattached display is not effecting reception. Therefore I deduced that it must be something else.
My next candidate is electrical noise from the DC motors. After all, I've taken NO precautions above those built into the NodeMCU module.
So why did the problems wait until now to surface? That might be the well known real estate answer - location, location, location. My "workshop" is in the basement and just a few feet from the Wireless Access Point (WAP). My tests yesterday were upstairs and much farther away from the WAP. That's one more theory to test and evaluate.