I was able to resolve the problem by uninstalling, rebooting, and reinstalling the program. I hadn't seen the previous post, so I didn't have or use the extra uninstall utility. All is well.
No offense, of course, but regardless of the URL and any wildcard that may have existed, it's certainly not an expected result that things didn't return to normal after removing the URL. So I feel pretty comfortable concluding that there's a bug in the exclusion feature.