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From what I can tell a large chunk of cladding people claim the cavity will be filled with insulation in such a way it's portrayed as solid and the cavity full which is clearly utter bs. I'm unsure but have a feeling claddings original uses as a temporary repair to a damaged wall dodge around some regs by placing it similar to scaffolding.
Clockwise-
I'm not really up for speculating, just pointing out that building regs does highlight these kinds of risks (fire spreading between compartments) and should prevent it. And that it's basic construction knowledge.
I think everyone involved in building construction (and maintenance) is feeling horribly uneasy and asking themselves if this could've happened on their watch, could they have contributed, directly or through inaction or negligence. It seems self-centred but it's on my mind.
hoefla
There should be firestops in that cavity behind the cladding so there are no voids bridging compartment floors (or walls but floors more important). That's pretty basic.
(The cladding itself should also not be easily combustible)