There's one thing I didn't touch and not sure if it can lead to an infinite place&break farm is what would happen with an unusual Silk Touch + Fortune combo, normal behavior is Silk Touch overrides when it happens.
Also if you test new fortune calculation along with previous cooldown cleanup on a test server would be good, just to make sure there isn't a mistake in code.
There's one thing I didn't touch and not sure if it can lead to an infinite place&break farm is what would happen with an unusual Silk Touch + Fortune combo, normal behavior is Silk Touch overrides when it happens.
Also if you test new fortune calculation along with previous cooldown cleanup on a test server would be good, just to make sure there isn't a mistake in code.