Bug#960304: snapshot.debian.org: Snapshot repo repeatedly cutting off connection, returning partial content

[Mike Hommey <mh+reportbug@glandium.org>]

Package: snapshot.debian.org
Followup-For: Bug #960304

Dear Maintainer,

We're hitting this problem regularly on Mozilla CI (from using dget),
and what is probably a variant of this bug with apt, which fails with,
for example:

[task 2021-08-05T21:27:09.094Z] Err:187 http://snapshot.debian.org/archive/debian/20210208T213147Z jessie/main amd64 adwaita-icon-theme all 3.14.0-2
[task 2021-08-05T21:27:09.094Z]   Undetermined Error [IP: 193.62.202.27 80]
(...)
[task 2021-08-05T21:27:23.590Z] Err:202 http://snapshot.debian.org/archive/debian/20210208T213147Z jessie/main amd64 libicu52 amd64 52.1-8+deb8u7
[task 2021-08-05T21:27:23.591Z]   Undetermined Error [IP: 193.62.202.27 80]
(...)
[task 2021-08-05T21:28:41.210Z] E: Failed to fetch http://snapshot.debian.org/archive/debian/20210208T213147Z/pool/main/a/adwaita-icon-theme/adwaita-icon-theme_3.14.0-2_all.deb  Undetermined Error [IP: 193.62.202.27 80]
[task 2021-08-05T21:28:41.210Z] E: Failed to fetch http://snapshot.debian.org/archive/debian/20210208T213147Z/pool/main/i/icu/libicu52_52.1-8+deb8u7_amd64.deb  Undetermined Error [IP: 193.62.202.27 80]

Corresponding server-side log for the same url:
54.162.202.139 - - [05/Aug/2021:21:27:08 +0000] "GET http://snapshot.debian.org/archive/debian/20210208T213147Z/pool/main/a/adwaita-icon-theme/adwaita-icon-theme_3.14.0-2_all.deb HTTP/1.1" 200 3518464 "-" "Debian APT-HTTP/1.3 (1.8.2.2)"
54.202.218.195 - - [05/Aug/2021:21:39:12 +0000] "GET http://snapshot.debian.org/archive/debian/20210208T213147Z/pool/main/a/adwaita-icon-theme/adwaita-icon-theme_3.14.0-2_all.deb HTTP/1.1" 200 9978092 "-" "Debian APT-HTTP/1.3 (1.8.2.2)"

Mike