Fenix 6 drop dead, but works when on charger

Hello all, 

did someone experience, that Fenix 6 just drop dead? Screen is black and non-response to any buttons. However, funny thing is, when I connect it to charger, it looks like operating normally. 

Btw, battery is around 70 %, so its not lack of energy.

Any ideas? Or device is to be sent to Garmin.