Inconsistent information returned by apt.puppetlabs.com

I have two servers in the same location, both of which resolve apt.puppetlabs.com the same way:

kestrel % host apt.puppetlabs.com
apt.puppetlabs.com is an alias for downloads.puppetlabs.com.
downloads.puppetlabs.com is an alias for burji3.puppetlabs.com.
burji3.puppetlabs.com has address 192.155.89.90
burji3.puppetlabs.com has IPv6 address 2600:3c03::f03c:91ff:fedb:6b1d

willow % host apt.puppetlabs.com
apt.puppetlabs.com is an alias for downloads.puppetlabs.com.
downloads.puppetlabs.com is an alias for burji3.puppetlabs.com.
burji3.puppetlabs.com has address 192.155.89.90
burji3.puppetlabs.com has IPv6 address 2600:3c03::f03c:91ff:fedb:6b1d

However, they're returning different data for at least the amd64 xenial packages:

kestrel % curl -s https://apt.puppetlabs.com/dists/xenial/PC1/binary-amd64/Packages | grep '1\.8\.2'
kestrel %

(so no output)

willow % curl -s https://apt.puppetlabs.com/dists/xenial/PC1/binary-amd64/Packages | grep '1\.8\.2'
Version: 1.8.2-1xenial
Filename: pool/xenial/PC1/p/puppet-agent/puppet-agent_1.8.2-1xenial_amd64.deb
willow %

So the first server isn't getting the latest packages because the package list is out of date.

I can't see how this is my fault, thus the ticket. My best guess is that burji3.puppetlabs.com is a load balancer and has multiple servers behind it, one of which isn't updating properly.