You have all the correct events, but they are in wrong places.
First event should have two conditions:
Crate HP<=0 : Crate start animation "Break"
Trigger once
Second event should also be top-level (not a sub-event):
Crate on animation "Break" finished : Start fade
However, this code may not work correctly if you have multiple instances of Crate object, because "Trigger once" doesn't work per instance. As long as one crate has HP<0, this event will not get triggered for other crates.
So I suggest you change your code to this:
Crate HP<=0 : Crate start animation "Break"
Crate animation "Break" NOT playing
Crate on animation "Break" finished : Start fade
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