Minimal repro:
hello_world_device := class(creative_device):
@editable Arr: []?[]?int = array{}
# Runs when the device is started in a running game
OnBegin<override>()<suspends>:void=
# TODO: Replace this with your code
Print("Hello, world!")
Print("2 + 2 = {2 + 2}")
Build, place that device in the world, try to set an int in that nested array