looks like an 3rd party app issue. i disable and forced stop my "Always On Edge" app. Screen timeout stays on what time i set it. You guys try it and let us know.
it's a 3rd party app...I do think it is the Always On Edge (AOE), like mine as well which started recently too...the app got updated recently as well with a very new interface and now it has premium access and isn't free as before..many setting you can't change now and many more was implemented....
I also have the AOE app installed and after seeing this post I realized that it updated a few days ago when this seemed to start. I went in and looked at the app in the store today and there was another update for the app. Since updating the app, my phone is now staying at the 30 timeout set it to and is no longer reverting back to the 8 second timeout. I would check to see if there is an update available and if not, maybe try to uninstal/reinstall the app to see if that fixes the issue.
I had the same issue it would keep setting the screen timeout back to 8 seconds and when i loaded my AOD app to check the settings to see if that was causing the issue i didnt find anything in there so i exited out of that app and it stopped resetting the screen timeout