A bit similar to X1C crashing into layers and Scratching PEI texture plate but much more dramatic. I’m almost done printing the AMS riser and the head decided to crash into the plate at the start of a print:
It went so deep it grinded the metal plate which ruined it, so I will have to buy a whole new one. 
That’s very annoying. I suspect the extruder is dead too. Anyone has an idea what could have happened? The location (middle on right side) where it hit the plate is odd because I was printing plate #9 which is a huge flat surface, one of the drawer.