The companies whose deployment processes I've seen did exactly that - after an update, a request to a CDN results in a fault which forces the CDN to query the o

The companies whose deployment processes I've seen did exactly that - after an update, a request to a CDN results in a fault which forces the CDN to query the original company server. In those cases, the static assets had to be distributed onto the servers. I would imagine Facebook does the same, but the article pretty explicitly says that they don't do that (which is why I imagine you got downvoted - for the record, I think that was inappropriate), which raises the question of what exactly do they do?