To answer your question, it was only the items in the left column of the "C/C++ Comments" Options screen. Changing other options, e.g. Extend leading border, Split line comments, etc. updated fine.
Then I noticed that my Backups and AutoSaves had not been working for over a month (it looked like they turned themselves off?). Wow that is a little scary ... and at shutdown SE was complaining about not being able to copy some file -- maybe vusrdef.e? -- which I had been blissfully ignoring.
In any case, after playing around with Backups and AutoSaves, the problem mentioned above solved itself and SE is cleanly shutting down again ... and Backups/AutoSaves are working again. So maybe this was self-inflicted by ignoring the warning at shutdown?