Welcome to the GLA forum Jun. I can't speak for your GLA, but that experience seems to be a random Mercedes Benz gremlin. I have had it three times. Once in a 2001 C-Class, the entire dash went dark. Fortunately it was on a 25 MPH street and I was able to pull over and "reboot," shutting down and re-starting, which resolved the issue. I have had a similar occurrence twice with my GLA. Once was on open highway at 60 MPH and the dash went dead, yet in a few seconds it came back to life as if nothing had happened. No fault could be found soon after by the dealer service department. Another time was while exiting highway...there was a quick dead dash and then return to normal. Your experience sounds similar to mine, but I can only provide anecdotal information, no technical solution.