Edge 840 takes 2-3 minutes to wake up and becomes completely dead/unresponsive for several times

I just got my Edge 840 for one day and rode with it once and it suddenly took 2-3 minutes to wake up, only showing the garmin logo when the power button is pressed, normally it takes 1 second right? And It became completely dead several times after that. IDK whether I got a faulty unit or what?

But I can notice that when I charge it using my macbook pro and the type-C cable, it turns itself off and again, only showing the garmin logo and the remaining battery, is this normal?