The class ElementUnitDamage calls the function "override_value_on_element_type", but doesn't define it.
If we look at the parentclass of ElementUnitDamage, we find CoreMissionScriptElement.MissionScriptElement, which doesn't define the function as well.
Now, there is a MissionScriptElement in 'lib/managers/mission' as well, and that one does declare the funtion and gets used by the call "CoreClass.override_class(CoreMissionScriptElement.MissionScriptElement, MissionScriptElement)" at the end of the file.
When shooting at targets (Wick's shooting range) in safehouse, you'll get the following crashlog:
The class ElementUnitDamage calls the function "override_value_on_element_type", but doesn't define it. If we look at the parentclass of ElementUnitDamage, we find CoreMissionScriptElement.MissionScriptElement, which doesn't define the function as well. Now, there is a MissionScriptElement in 'lib/managers/mission' as well, and that one does declare the funtion and gets used by the call "CoreClass.override_class(CoreMissionScriptElement.MissionScriptElement, MissionScriptElement)" at the end of the file.