security.debian.org hosts have different content

[Mike Bird <mgb-debian@yosemite.net>]

I just noticed that when we rsync from security.debian.org
we're generating a lot of traffic because
rsync://security.debian.org/debian-security/dists/potato/
exists on some security.debian.org hosts and not on others.
One rsync will delete several hundred MB and the next will
download it again.

Am I naive in thinking the various hosts to which DNS maps
security.debian.org should have the same content, modulo
minor transient differences?

--Mike Bird