Hi Rich,
Thanks for the file. It did not however change behavior.
I did as you suggested. I figured you didn't need to see extraneous touchpad events, so I slept the `udevadm trigger` a few seconds while I navigated to the other terminal. Also, I left 99-touch.rules in /etc/udev/rules.d
touch.txt is attached, - actually touch.txt.gz, since even after editing out some heading and trailing chatter about the power supply, the file was longer than the max size permitted. Let me know if the liberties I took were counterproductive.
I appreciate the help. As I say, this is not a problematic bug but one I've noticed for quite a while, and it's nice to get some insight.