This problem has been around for years, with many previous versions of windows. I do not remember a version that did not have this problem.
Never really worked out what turns the Auto Hide option off, do not think its going to sleep or a restart.
I work all the time on a laptop and rerly reboot, just close the screen to put it into standby. I do have 3 x 28" monitors plugged in during the daytime (at my desk) and just use the built in monotor in the evening ( on my lap).
All seems pretty random when the Auto Hide option turns off.