Failed to fetch http://mirror.dfw.rax.openstack.org/ubuntu/dists/bionic-updates/universe/binary-amd64/Packages.gz File has unexpected size (1257053 != 1257062). Mirror sync in progress?

Seen here: http://logs.openstack.org/84/653084/2/check/openstack-tox-docs/6591b3c/job-output.txt#_2019-04-16_20_41_45_442118

2019-04-16 20:41:43.001944 | ubuntu-bionic | Err:15 http://mirror.dfw.rax.openstack.org/ubuntu bionic-updates/universe amd64 Packages
2019-04-16 20:41:43.002336 | ubuntu-bionic | File has unexpected size (1257053 != 1257062). Mirror sync in progress? [IP: 2001:4800:7817:103:be76:4eff:fe04:652a 80]
2019-04-16 20:41:43.002428 | ubuntu-bionic | Hashes of expected file:
2019-04-16 20:41:43.002518 | ubuntu-bionic | - Filesize:1257062 [weak]
2019-04-16 20:41:43.002703 | ubuntu-bionic | - SHA256:1fa8a8095c008824ed2e85796de774ff146a97a40bad235caa6882367f5bc30f
2019-04-16 20:41:43.002833 | ubuntu-bionic | - SHA1:830d76604a6128b91b8676c13da967188515c222 [weak]
2019-04-16 20:41:43.002951 | ubuntu-bionic | - MD5Sum:e83ec52ad207fa9128fbbef0cbadcc29 [weak]
2019-04-16 20:41:43.003080 | ubuntu-bionic | Release file created at: Tue, 16 Apr 2019 18:48:41 +0000
2019-04-16 20:41:43.004839 | ubuntu-bionic | Get:16 http://mirror.dfw.rax.openstack.org/ubuntu bionic-updates/main amd64 Packages [830 kB]
2019-04-16 20:41:43.005122 | ubuntu-bionic | Err:16 http://mirror.dfw.rax.openstack.org/ubuntu bionic-updates/main amd64 Packages
2019-04-16 20:41:43.005176 | ubuntu-bionic |
2019-04-16 20:41:43.006501 | ubuntu-bionic | Get:17 http://mirror.dfw.rax.openstack.org/ubuntu bionic-backports/universe amd64 Packages [4023 B]
2019-04-16 20:41:43.006831 | ubuntu-bionic | Get:18 http://mirror.dfw.rax.openstack.org/ubuntu bionic-backports/main amd64 Packages [1043 B]
2019-04-16 20:41:43.007488 | ubuntu-bionic | Get:19 http://mirror.dfw.rax.openstack.org/ubuntu bionic-security/universe amd64 Packages [392 kB]
2019-04-16 20:41:43.014416 | ubuntu-bionic | Get:20 http://mirror.dfw.rax.openstack.org/ubuntu bionic-security/main amd64 Packages [438 kB]
2019-04-16 20:41:44.351931 | ubuntu-bionic | Fetched 14.7 MB in 2s (8557 kB/s)
2019-04-16 20:41:45.405159 | ubuntu-bionic | Reading package lists...
2019-04-16 20:41:45.442118 | ubuntu-bionic | E: Failed to fetch http://mirror.dfw.rax.openstack.org/ubuntu/dists/bionic-updates/universe/binary-amd64/Packages.gz File has unexpected size (1257053 != 1257062). Mirror sync in progress? [IP: 2001:4800:7817:103:be76:4eff:fe04:652a 80]
2019-04-16 20:41:45.442279 | ubuntu-bionic | Hashes of expected file:
2019-04-16 20:41:45.442365 | ubuntu-bionic | - Filesize:1257062 [weak]
2019-04-16 20:41:45.442535 | ubuntu-bionic | - SHA256:1fa8a8095c008824ed2e85796de774ff146a97a40bad235caa6882367f5bc30f
2019-04-16 20:41:45.442666 | ubuntu-bionic | - SHA1:830d76604a6128b91b8676c13da967188515c222 [weak]
2019-04-16 20:41:45.442786 | ubuntu-bionic | - MD5Sum:e83ec52ad207fa9128fbbef0cbadcc29 [weak]
2019-04-16 20:41:45.443035 | ubuntu-bionic | Release file created at: Tue, 16 Apr 2019 18:48:41 +0000
2019-04-16 20:41:45.443278 | ubuntu-bionic | E: Failed to fetch http://mirror.dfw.rax.openstack.org/ubuntu/dists/bionic-updates/main/binary-amd64/Packages.gz
2019-04-16 20:41:45.443485 | ubuntu-bionic | E: Some index files failed to download. They have been ignored, or old ones used instead.
2019-04-16 20:41:45.791780 | ubuntu-bionic | ERROR
2019-04-16 20:41:45.792222 | ubuntu-bionic | {
2019-04-16 20:41:45.792367 | ubuntu-bionic | "delta": "0:00:02.876860",
2019-04-16 20:41:45.792501 | ubuntu-bionic | "end": "2019-04-16 20:41:45.444527",
2019-04-16 20:41:45.792627 | ubuntu-bionic | "msg": "non-zero return code",
2019-04-16 20:41:45.792735 | ubuntu-bionic | "rc": 100,
2019-04-16 20:41:45.792858 | ubuntu-bionic | "start": "2019-04-16 20:41:42.567667"
2019-04-16 20:41:45.792961 | ubuntu-bionic | }

Looks like this happens on multiple providers but only on bionic nodes:

http://logstash.openstack.org/#dashboard/file/logstash.json?query=message%3A%5C%22Failed%20to%20fetch%5C%22%20AND%20message%3A%5C%22File%20has%20unexpected%20size%5C%22%20AND%20message%3A%5C%22Mirror%20sync%20in%20progress%3F%5C%22%20AND%20tags%3A%5C%22console%5C%22&from=7d