I can't really think of any reason as to why this would happen, but lately my laptop has been acting a bit odd. It is an HP Pavilion g7 2017cl.
This has happened now twice - the screen will slowly (over a period of about 10 seconds) fade into a much higher contrast that's really annoying to look at. The only explanation is that I hibernate my computer a lot instead of shutting down/restarting.
It seems to be fixed after a restart, but obviously I'd like to fix the main problem instead of just making it go away for a week.