after a print, the printer goes into reset position which is at the very top.
when the printer is shutdown in that position, the arm instantly drops and crashes with the nozzle on the build plate.
how is the printer supposed to be shutdown?
Since all axes are belt-driven, the arm will fall under its weight when the stepper motors aren't powered.
Some people have created clips/hooks or other ways of keeping the arm from hitting the bed.
I've found it easy enough to simply hold the axis, turn off main power and then lower the axis gently to the bed.