Cannot mirror mongodb-org debian. Possible index mismatch?

I’m adapting reprepro for use with the apt repository for MongoDB CE. This is so my team can mirror the MongoDB packages we want without trusting more than our own public key.

Here is the conf/updates file used to sync with repo.mongodb.org

Name: buster-mongodb
Method: https://repo.mongodb.org/apt/debian/
Suite: */mongodb-org/6.0
Components: main
Architectures: amd64
GetInRelease: no
VerifyRelease: 6A26B1AE64C3C388

Name: bullseye-mongodb
Method: https://repo.mongodb.org/apt/debian/
Suite: */mongodb-org/6.0
Components: main
Architectures: amd64
GetInRelease: no
VerifyRelease: 6A26B1AE64C3C388

reprepro --logdir ./logs -b . --noskipold update prints

aptmethod got 'https://repo.mongodb.org/apt/debian/dists/bullseye/mongodb-org/6.0/Release'
aptmethod got 'https://repo.mongodb.org/apt/debian/dists/bullseye/mongodb-org/6.0/Release.gpg'
aptmethod got 'https://repo.mongodb.org/apt/debian/dists/buster/mongodb-org/6.0/Release'
aptmethod got 'https://repo.mongodb.org/apt/debian/dists/buster/mongodb-org/6.0/Release.gpg'
Calculating packages to get...
ERROR: Same file is requested with conflicting checksums:
md5 expected: 820201311332410d875e594f14af47db, got: ad7923dea5bffa7cdd2ecefa5f13d7df
sha1 expected: 708ad9650060ea3411b79ef6fb2bc24d29efea91, got: 29a96ba4f40b8fd491ee71c81ffa46b8321cbc24
sha256 expected: fe802bcdcb9a39fea564c6de4dc2537b70f518dfb2172ed034fe466ff3138429, got: d168b11caf956e0be43655406a752eb7aa5cca406acb1c005d3eb56562948de0
size expected: 47694664, got: 47735588
There have been errors!

Two things strike me as odd:

  1. The expected checksum is not in either downloaded Release file, despite using HTTPS to rule out a MITM
  2. The size difference is a clear indication of a checksum mismatch.

I expect it’s more likely I made a mistake than the repo.mongodb.org index being out of date. What should I check next?