okey i managed to remake the crash,
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FATAL ERROR in
action number 1
of Step Event0
for object obj_npc:
Variable <unknown_object>.y(1, -2147483648) not set before reading it.
at gml_Object_obj_npc_Step_0
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stack frame is
gml_Object_obj_npc_Step_0 (line -1)
while in Ellie's first mission, there were 3 enemies left to kill, the game crashed right after me and my friends collected all the metal in the up right corner.