I have added 'taskset -pa 1 $(pgrep -x Xorg)' to the rcX.d set of things. So initially the computer came up with my workaround in place. I reversed that with 'sudo taskset -pa 3 $(pgrep -x Xorg)' before connecting the external monitor.
All of this was about an hour after the computer was booted up at 6:57.
One more thing I should add about this sequence.
I have added 'taskset -pa 1 $(pgrep -x Xorg)' to the rcX.d set of things. So initially the computer came up with my workaround in place. I reversed that with 'sudo taskset -pa 3 $(pgrep -x Xorg)' before connecting the external monitor.
All of this was about an hour after the computer was booted up at 6:57.