I uninstalled several apps that I suspected may be causing the problem. The setting stayed at 2 minutes. I then reinstalled the apps, one by one, and it is still holding. One of the app installations must have been corrupt and reinstalling appears to have solved it. Yeah!!
The problem came back and I determined that it is caused by Notifier Pro. I changed the screen timeout setting in the app to 2 minutes but my screen timeout in the phone settings continues to revert to 30 sec. Notifier Pro is outta here.