I have installed the latest updates and the diagnostic tool found no problems.
Recently I have been constantly experiencing this brightness problem and nothing seems to help. When I close the typecover and later open it, the brightness of screen will be unable to be adjusted. Of course, a restart can fix this problem, but I don't want to restart my surface every time I run into this problem. Otherwise it will defeat the purpose of closing typecover instead of shutting down in the first place.