"Controller Malfunction"Mavic 2 Pro standard controller.

[offtheback]

Got the title or similar words while flying.Bars indicated maximum strength.No obstructions,drone 200' away clear line of sight about 100' high.Got this 3 times today 2 separate batteries.Drone returned to home.One time I shut off controller and restarted and it was ok.Scene on Crystal Sky froze.Any ideas as to what causes this?