An instrument panel display that fails to show critical safety information, such as engine coolant temperature or electrical charge increases the risk of a crash or injury.
The instrument panel cluster combination meter may fail to display certain warnings or indicators. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard (FMVSS) number 101, "Control and Displays" and in addition, for the subject Mirai vehicles, FMVSS 305, "Electric-powered vehicles: Electrolyte Spillage and Electrical Shock Protection."
What to do: Book it in at your next service. There is no deadline and no charge.