Crash with vicious tunneler (Red worm with blades) and crazed lepper (summoned)

v.0.0.36

I am using saia, the perk to summon the rest of the party, nighttaker, daybreaker.
game crashed as saia landed a killing blow on an enemy with 3~4 debuffs at the start of turn.


############################################################################################
FATAL ERROR in
action number 1
of Step Event0
for object obj_battlecontroller:

trying to index a variable which is not an array
at gml_Script_bc_OnDeath
############################################################################################

stack frame is
gml_Script_bc_OnDeath (line -1)
gml_Script_bc_ExecuteEvents
gml_Object_obj_battlecontroller_Step_0