it has happened to me when i put the car in neuteral to coast and then put it back on drive and turn on cruise control. If this sequence is done very quickly then cruise control gets disabled.
In the beginning it would not set the cruise control and i would just set it again. Later in version 6.0 (update done by a ranger at my home) it gave me the message pull over when its safe. I knew about it so i never pulled over as the message appeared as soon as put the car back on drive from neutral while coasting and then pulled the cruise stalk for cruise. Now if i do it it disables cruise control cant set it again.
I have never tried to reset displays as i know one solution is to turn off then turn the car back on. I usually do that on a red light or just wait till get to work or home.