I just noticed that and I am not sure whether that is the intended behavior (and I hope so as it makes sense, yet I cannot find any documentation):
If an event selects objects (like Enemy collides Enemy), the ForEech enemy only iterates through those two enemies.
If the object is not selected by the event (like Timer>0), then all Enemies are iterated with ForEach enemy.
I ask as I have seen so many answers where people state "it goes through all instances".