Partial clone - bad pack header?

I tried to do a partial clone, but it gave me a "bad pack header". Is there anything I can do to debug this?

I did "git config uploadpack.allowfilter true" in my repo.
Then I went to a scratch directory and did:
$ git clone --filter=blob:limit=10M ssh://localhost/~/git/my_big_repo
remote: Enumerating objects: 1619425, done.
remote: Counting objects: 100% (1619425/1619425), done.
remote: Compressing objects: 100% (362435/362435), done.
remote: Total 1619425 (delta 1225623), reused 1604277 (delta 1211975)
Receiving objects: 100% (1619425/1619425), 10.34 GiB | 35.61 MiB/s, done.
Resolving deltas: 100% (1225623/1225623), done.
Note: checking out 'a943f529b4781f34602f1ad5aab99a8699975c29'.

You are in 'detached HEAD' state. You can look around, make experimental changes and commit them, and you can discard any commits you make in this state without impacting any branches by performing another checkout.

If you want to create a new branch to retain commits you create, you may do so (now or later) by using -b with the checkout command again. Example:

  git checkout -b <new-branch-name>

fatal: the remote end hung up unexpectedly fatal: protocol error: bad pack header warning: Clone succeeded, but checkout failed. You can inspect what was checked out with 'git status' and retry the checkout with 'git checkout -f HEAD'

$ git checkout origin/master fatal: the remote end hung up unexpectedly fatal: protocol error: bad pack header

$ git --version git version 2.20.1.611.gfbb209baf1

There's plenty of disk space left.

Thanks, Luke